Low power high voltage generators are widely used in flaw detection, for powering portable particle accelerators, X-ray and cathode-ray tubes, photomultipliers, and ionizing radiation detectors. In addition, they are also used for electropulse destruction of solids, obtaining ultrafine powders, synthesizing new materials, as spark leak detectors, for launching gas-discharge light sources, for electric-discharge diagnostics of materials and products, for obtaining gas-discharge photographs using the S.D. Kirlian method, and for testing the quality of high-voltage insulation. In everyday life, such devices are used as power sources for electronic traps of ultrafine and radioactive dust, electronic ignition systems, for electro-fluvial chandeliers (chandeliers by A. L. Chizhevsky), air ionizers, medical devices (D’Arsonval apparatus, franklization, ultratonotherapy), gas lighters, electric fences, electric shockers, etc.
Conventionally, high voltage generators include devices that generate voltages above 1 kV.
The high-voltage pulse generator using a resonant transformer (Fig. 11.1) is made according to the classical scheme on a gas discharger RB-3.
Capacitor C2 is charged by a pulsating voltage through diode VD1 and resistor R1 to the breakdown voltage of the gas discharger. As a result of the breakdown of the gas gap of the arrester, the capacitor is discharged onto the primary winding of the transformer, after which the process is repeated. As a result, at the output of the transformer T1, damped high-voltage pulses with an amplitude of up to 3 ... 20 kV are formed.
To protect the output winding of the transformer from overvoltage, a surge arrester is connected in parallel to it, made in the form of electrodes with an adjustable air gap.
Rice. 11.1. Scheme of a high-voltage pulse generator using a gas discharger.
Rice. 11.2. Scheme of a high-voltage pulse generator with voltage doubling.
Transformer T1 of the pulse generator (Fig. 11.1) is made on an open ferrite core M400NN-3 with a diameter of 8 and a length of 100 mm. The primary (low-voltage) winding of the transformer contains 20 turns of wire MGShV 0.75 mm with a winding pitch of 5 ... 6 mm. The secondary winding contains 2400 turns of ordinary winding of wire PEV-2 0.04 mm. The primary winding is wound over the secondary winding through a polytetrafluoroethylene (fluoroplastic) gasket 2x0.05 mm. The secondary winding of the transformer must be reliably isolated from the primary.
An embodiment of a high-voltage pulse generator using a resonant transformer is shown in fig. 11.2. In this generator circuit there is a galvanic isolation from the mains. The mains voltage is supplied to the intermediate (step-up) transformer T1. The voltage removed from the secondary winding of the network transformer is supplied to the rectifier, which operates according to the voltage doubling scheme.
As a result of the operation of such a rectifier, a positive voltage appears on the upper plate of the capacitor C2 relative to the neutral wire, equal to the square root of 2Uii, where Uii is the voltage on the secondary winding of the power transformer.
A corresponding voltage of the opposite sign is formed on the capacitor C1. As a result, the voltage on the plates of the capacitor C3 will be equal to 2 square roots of 2Uii.
The charge rate of capacitors C1 and C2 (C1=C2) is determined by the resistance value R1.
When the voltage on the plates of the capacitor C3 equals the breakdown voltage of the gas discharger FV1, a breakdown of its gas gap will occur, the capacitor C3 and, accordingly, the capacitors C1 and C2 will be discharged, periodic damped oscillations will occur in the secondary winding of the transformer T2. After the capacitors are discharged and the arrester is turned off, the process of charging and subsequent discharge of the capacitors to the primary winding of the transformer 12 will be repeated again.
The high-voltage generator used to take photographs in a gas discharge, as well as to collect ultrafine and radioactive dust (Fig. 11.3) consists of a voltage doubler, a relaxation pulse generator and a step-up resonant transformer.
The voltage doubler is made on diodes VD1, VD2 and capacitors C1, C2. The charging chain is formed by capacitors C1 C3 and resistor R1. In parallel with the capacitors C1 SZ, a 350 V gas discharger is connected with the primary winding of the step-up transformer T1 connected in series.
As soon as the level of direct voltage on the capacitors C1 SZ exceeds the breakdown voltage of the arrester, the capacitors are discharged through the winding of the step-up transformer and as a result a high-voltage pulse is formed. The circuit elements are chosen so that the frequency of pulse formation is about 1 Hz. Capacitor C4 is designed to protect the output terminal of the device from the ingress of mains voltage.
Rice. 11.3. Scheme of a high voltage pulse generator using a gas discharger or dinistors.
The output voltage of the device is entirely determined by the properties of the transformer used and can reach 15 kV. A high-voltage transformer for an output voltage of about 10 kV is made on a dielectric tube with an outer diameter of 8 mm and a length of 150 mm, a copper electrode with a diameter of 1.5 mm is located inside. The secondary winding contains 3 ... 4 thousand turns of PELSHO 0.12 wire, wound turn to turn in 10 ... 13 layers (winding width 70 mm) and impregnated with BF-2 glue with polytetrafluoroethylene interlayer insulation. The primary winding contains 20 turns of PEV 0.75 wire passed through a PVC cambric.,
As such a transformer, you can also use a modified horizontal TV output transformer; transformers for electronic lighters, flash lamps, ignition coils, etc.
The R-350 gas discharger can be replaced by a switchable chain of KN102 type dynistors (Fig. 11.3, on the right), which will allow the output voltage to be changed in steps. To evenly distribute the voltage across the dinistors, resistors of the same rating with a resistance of 300 ... 510 kOhm are connected in parallel to each of them.
A variant of the high-voltage generator circuit using a gas-filled device thyratron as a threshold-switching element is shown in fig. 11.4.
Rice. 11.4. Scheme of a high voltage pulse generator using a thyratron.
The mains voltage is rectified by the diode VD1. The rectified voltage is smoothed by the capacitor C1 and supplied to the charging circuit R1, C2. As soon as the voltage on the capacitor C2 reaches the ignition voltage of the thyratron VL1, it flashes. Capacitor C2 is discharged through the primary winding of transformer T1, the thyratron goes out, the capacitor starts charging again, etc.
An automobile ignition coil was used as a transformer T1.
Instead of the thyratron VL1 MTX-90, one or more dinistors of the KN102 type can be included. The high voltage amplitude can be adjusted by the number of included dinistors.
The design of a high-voltage converter using a thyratron switch is described in the work. Note that other types of gas-filled devices can also be used to discharge the capacitor.
More promising is the use of semiconductor switching devices in modern high-voltage generators. Their advantages are clearly expressed: these are high repeatability of parameters, lower cost and dimensions, high reliability.
Below we will consider high-voltage pulse generators using semiconductor switching devices (dinistors, thyristors, bipolar and field-effect transistors).
Quite equivalent, but low-current analogue of gas dischargers are dinistors.
On fig. 11.5 shows the electrical circuit of a generator made on dinistors. In its structure, the generator is completely similar to those described earlier (Fig. 11.1, 11.4). The main difference lies in the replacement of the gas discharger with a chain of series-connected dinistors.
Rice. 11.5. Scheme of a high-voltage pulse generator on dinistors.
Rice. 11.6. Diagram of a high-voltage pulse generator with a bridge rectifier.
It should be noted that the efficiency of such an analogue and switching currents is noticeably lower than that of the prototype, however, dinistors are more affordable and more durable.
A somewhat complicated version of the high-voltage pulse generator is shown in Fig. 11.6. Mains voltage is supplied to the bridge rectifier on diodes VD1 VD4. The rectified voltage is smoothed by capacitor C1. A constant voltage of about 300 V is formed on this capacitor, which is used to power a relaxation oscillator made up of elements R3, C2, VD5 and VD6. Its load is the primary winding of the transformer T1. Pulses with an amplitude of approximately 5 kV and a repetition rate of up to 800 Hz are taken from the secondary winding.
The chain of dinistors must be designed for a turn-on voltage of about 200 V. Here you can use dinistors of the KN102 or D228 type. In this case, it should be borne in mind that the turn-on voltage of dinistors of the KN102A, D228A type is 20 V; KN102B, D228B 28 V; KN102V, D228V 40 V; KN102G, D228G 56 V; KN102D, D228D 80 V; KN102E 75 V; KN102Zh, D228Zh 120 V; KN102I, D228I 150 V.
As a transformer T1 in the above devices, a modified horizontal transformer from a black and white TV can be used. Its high-voltage winding is left, the rest are removed and instead of them, a low-voltage (primary) winding is wound 15 ... 30 turns of PEV wire with a diameter of 0.5 ... 0.8 mm.
When choosing the number of turns of the primary winding, the number of turns of the secondary winding should be taken into account. It must also be borne in mind that the magnitude of the output voltage of the high-voltage pulse generator depends to a greater extent on the tuning of the transformer circuits to resonance, rather than on the ratio of the number of turns of the windings.
The characteristics of some types of horizontal television transformers are shown in Table 11.1.
Table 11.1. Parameters of high-voltage windings of unified line-scan television transformers.
| Transformer type | Number of turns | R windings, Ohm |
|
| TVS-A, TVS-B | |||
| TVS-110, TVS-110M | |||
| Transformer type | Number of turns | R windings, Ohm |
|
| TVS-90LTs2, TVS-90LTs2-1 | |||
| TVS-110PTs15 | |||
| TVS-110PTs16, TVS-110PTs18 |
Rice. 11.7. The electrical circuit of the high-voltage pulse generator.
On fig. 11.7 shows a diagram of a two-stage high-voltage pulse generator published on one of the sites, in which a thyristor is used as a switching element. In turn, as a threshold element that determines the repetition rate of high-voltage pulses and triggers the thyristor, a gas-discharge device, a neon lamp (chain HL1, HL2), was chosen.
When the supply voltage is applied, the pulse generator, made on the basis of the VT1 transistor (2N2219A KT630G), generates a voltage of about 150 V. This voltage is rectified by the VD1 diode and charges the capacitor C2.
After the voltage on the capacitor C2 exceeds the ignition voltage of the neon lamps HL1, HL2, the capacitor will be discharged through the current-limiting resistor R2 to the control electrode of the thyristor VS1, the thyristor will open. The discharge current of the capacitor C2 will create electrical oscillations in the primary winding of the transformer T2.
The thyristor turn-on voltage can be adjusted by selecting neon lamps with different ignition voltages. You can stepwise change the thyristor turn-on voltage by switching the number of neon lamps connected in series (or dinistors replacing them).
Rice. 11.8. Diagram of electrical processes on the electrodes of semiconductor devices (to Fig. 11.7).
The voltage diagram at the base of the transistor VT1 and at the anode of the thyristor is shown in fig. 11.8. As follows from the presented diagrams, the blocking oscillator pulses have a duration of approximately 8 ms. The charge of the capacitor C2 occurs stepwise-exponentially in accordance with the action of pulses taken from the secondary winding of the transformer T1.
At the output of the generator, pulses with a voltage of approximately 4.5 kV are formed. As a transformer T1, an output transformer for low-frequency amplifiers was used. As
high-voltage transformer T2, a flash transformer or a recycled (see above) horizontal scanning television transformer was used.
A diagram of another version of the generator using a neon lamp as a threshold element is shown in fig. 11.9.
Rice. 11.9. The electrical circuit of the generator with a threshold element on a neon lamp.
The relaxation generator in it is made on the elements R1, VD1, C1, HL1, VS1. It works with positive loop-periods of the mains voltage, when the capacitor C1 is charged to the turn-on voltage of the threshold element on the neon lamp HL1 and the thyristor VS1. Diode VD2 dampens self-induction pulses of the primary winding of the step-up transformer T1 and allows you to increase the output voltage of the generator. The output voltage reaches 9 kV. The neon lamp is also a signaling device for connecting the device to the network.
The high-voltage transformer is wound on a segment of a rod with a diameter of 8 and a length of 60 mm made of M400NN ferrite. First, place the primary winding 30 turns of wire PELSHO 0.38, and then the secondary 5500 turns PELSHO 0.05 or larger diameter. Between the windings and every 800 ... 1000 turns of the secondary winding, an insulation layer is laid from a PVC insulating tape.
In the generator, it is possible to introduce a discrete multi-stage adjustment of the output voltage by switching in a series circuit of neon lamps or dinistors (Fig. 11.10). In the first variant, two steps of regulation are provided, in the second up to ten or more (when using KN102A dinistors with a switching voltage of 20 V).
Rice. 11.10. Electrical circuit of the threshold element.
Rice. 11.11. The electrical circuit of the high voltage generator with a threshold element on the diode.
A simple high voltage generator (Fig. 11.11) allows you to get output pulses with an amplitude of up to 10 kV.
Switching of the control element of the device occurs at a frequency of 50 Hz (on one half-wave of the mains voltage). As a threshold element, a VD1 D219A (D220, D223) diode was used, which operates with a reverse bias in the avalanche breakdown mode.
When the avalanche breakdown voltage is exceeded at the semiconductor junction of the diode, the diode transitions to the conducting state. The voltage from the charged capacitor C2 is applied to the control electrode of the thyristor VS1. After turning on the thyristor, the capacitor C2 is discharged onto the winding of the transformer T1.
Transformer T1 has no core. It is made on a coil with a diameter of 8 mm from polymethyl methacrylate or polytetrachlorethylene and contains three spaced sections with a width of
9 mm. The step-up winding contains 3x1000 turns wound with PET wire, PEV-2 0.12 mm. After winding, the winding must be impregnated with paraffin. 2 3 layers of insulation are applied over the paraffin, after which the primary winding is wound 3x10 turns of PEV-2 wire 0.45 mm.
Thyristor VS1 can be replaced by another for a voltage above 150 V. The avalanche diode can be replaced by a chain of dinistors (Fig. 11.10, 11.11 below).
The circuit of a low-power portable source of high-voltage pulses with autonomous power supply from one galvanic cell (Fig. 11.12) consists of two generators. The first is built on two low-power transistors, the second on a thyristor and a dinistor.
Rice. 11.12. Scheme of a voltage generator with a low-voltage supply and a thyristor-dinistor key element.
The cascade on transistors of different conductivity converts low-voltage direct voltage into high-voltage pulsed voltage. The timing chain in this generator is the elements C1 and R1. When the power is turned on, the VT1 transistor opens, and the voltage drop across its collector opens the VT2 transistor. Capacitor C1, charging through resistor R1, reduces the base current of transistor VT2 so much that transistor VT1 goes out of saturation, and this leads to closing of VT2. The transistors will be closed until the capacitor C1 is discharged through the primary winding of the transformer T1.
The increased pulse voltage taken from the secondary winding of the transformer T1 is rectified by the diode VD1 and fed to the capacitor C2 of the second generator with a thyristor VS1 and a dinistor VD2. In each positive half cycle
the storage capacitor C2 is charged to the amplitude value of the voltage equal to the switching voltage of the dinistor VD2, i.e. up to 56 V (nominal pulse triggering voltage for dinistor type KN102G).
The transition of the dinistor to the open state affects the control circuit of the thyristor VS1, which in turn also opens. Capacitor C2 is discharged through the thyristor and the primary winding of the transformer T2, after which the dinistor and thyristor close again and the next charge of the capacitor begins the switching cycle is repeated.
Pulses with an amplitude of several kilovolts are taken from the secondary winding of the transformer T2. The frequency of spark discharges is approximately 20 Hz, but it is much less than the frequency of pulses taken from the secondary winding of the transformer T1. This happens because the capacitor C2 is charged to the switching voltage of the dinistor not in one, but in several positive half-cycles. The capacitance value of this capacitor determines the power and duration of the output discharge pulses. The average value of the discharge current, which is safe for the dinistor and the control electrode of the trinistor, is chosen based on the capacitance of this capacitor and the magnitude of the pulse voltage supplying the cascade. To do this, the capacitance of the capacitor C2 should be approximately 1 uF.
Transformer T1 is made on an annular ferrite magnetic circuit of the K10x6x5 type. It has 540 turns of PEV-2 0.1 wire with a grounded outlet after the 20th turn. The beginning of its winding is connected to the transistor VT2, the end to the diode VD1. The T2 transformer is wound on a coil with a ferrite or permalloy core with a diameter of 10 mm and a length of 30 mm. A coil with an outer diameter of 30 mm and a width of 10 mm is wound with a PEV-2 wire of 0.1 mm until the frame is completely filled. Before the end of the winding, a grounded tap is made, and the last row of wire of 30 ... 40 turns is wound round to round over the insulating layer of varnished fabric.
Transformer T2 in the course of winding must be impregnated with insulating varnish or BF-2 glue, then dried thoroughly.
Instead of VT1 and VT2, you can use any low-power transistors that can operate in a pulsed mode. Thyristor KU101E can be replaced with KU101G. Power source galvanic cells with a voltage of not more than 1.5 V, for example, 312, 314, 316, 326, 336, 343, 373, or disk nickel-cadmium batteries of the type D-0.26D, D-0.55S, etc.
The thyristor generator of high-voltage pulses with mains supply is shown in fig. 11.13.
Rice. 11.13. Electric circuit of a high-voltage pulse generator with a capacitive energy storage and a thyristor-based switch.
During the positive half-cycle of the mains voltage, the capacitor C1 is charged through the resistor R1, the diode VD1 and the primary winding of the transformer T1. At the same time, the thyristor VS1 is closed, since there is no current through its control electrode (the voltage drop across the VD2 diode in the forward direction is small compared to the voltage required to open the thyristor).
With a negative half-cycle, the diodes VD1 and VD2 close. A voltage drop is formed on the thyristor cathode relative to the control electrode (minus on the cathode, plus on the control electrode), a current appears in the control electrode circuit, and the thyristor opens. At this moment, the capacitor C1 is discharged through the primary winding of the transformer. A high voltage pulse appears in the secondary winding. And so each period of mains voltage.
At the output of the device, bipolar high-voltage pulses are formed (since damped oscillations occur when the capacitor is discharged in the primary winding circuit).
Resistor R1 can be made up of three MLT-2 resistors connected in parallel with a resistance of 3 kOhm.
Diodes VD1 and VD2 must be rated for a current of at least 300 mA and a reverse voltage of at least 400 V (VD1) and 100 B (VD2). Capacitor C1 of the MBM type for a voltage of at least 400 V. Its capacitance fractions of a microfarad is selected experimentally. Thyristor VS1 type KU201K, KU201L, KU202K KU202N. Transformers ignition coil B2B (6 V) from a motorcycle or car.
The TVS-110L6, TVS-1 YULA, TVS-110AM horizontal scanning transformer can be used in the device.
A fairly typical circuit of a high-voltage pulse generator with a capacitive energy storage is shown in fig. 11.14.
Rice. 11.14. Scheme of a thyristor generator of high-voltage pulses with a capacitive energy storage.
The generator contains a quenching capacitor C1, a diode rectifier bridge VD1 VD4, a thyristor switch VS1 and a control circuit. When the device is turned on, capacitors C2 and C3 are charged, the thyristor VS1 is still closed and does not conduct current. The limit voltage on the capacitor C2 is limited by the zener diode VD5 to 9V. In the process of charging the capacitor C2 through the resistor R2, the voltage on the potentiometer R3 and, accordingly, on the control transition of the thyristor VS1 increases to a certain value, after which the thyristor switches to a conducting state, and the capacitor C3 through the thyristor VS1 is discharged through the primary (low-voltage) winding of the transformer T1, generating a high-voltage pulse. After that, the thyristor closes and the process starts again. Potentiometer R3 sets the thyristor threshold VS1.
The pulse repetition frequency is 100 Hz. An automotive ignition coil can be used as a high voltage transformer. In this case, the output voltage of the device will reach 30...35 kV. The thyristor generator of high-voltage pulses (Fig. 11.15) is controlled by voltage pulses taken from a relaxation generator made on a VD1 dinistor. The operating frequency of the control pulse generator (15 ... 25 Hz) is determined by the value of the resistance R2 and the capacitance of the capacitor C1.
Rice. 11.15. The electrical circuit of the thyristor generator of high-voltage pulses with pulse control.
The relaxation generator is connected to the thyristor switch through a pulse transformer T1 of the MIT-4 type. As an output transformer T2, a high-frequency transformer from the Iskra-2 darsonvalization apparatus is used. The output voltage of the device can reach up to 20...25 kV.
On fig. 11.16 shows the option of supplying control pulses to the thyristor VS1.
The voltage converter (Fig. 11.17), developed in Bulgaria, contains two stages. In the first of them, the load of the key element, made on the transistor VT1, is the winding of the transformer T1. The control pulses of a rectangular shape periodically turn on / off the key on the transistor VT1, thereby connecting / disconnecting the primary winding of the transformer.
Rice. 11.16. Thyristor switch control option.
Rice. 11.17. Electrical circuit of a two-stage high-voltage pulse generator.
In the secondary winding, an increased voltage is induced, proportional to the transformation ratio. This voltage is rectified by the diode VD1 and charges the capacitor C2, which is connected to the primary (low-voltage) winding of the high-voltage transformer T2 and the thyristor VS1. The operation of the thyristor is controlled by voltage pulses taken from the additional winding of the transformer T1 through a chain of elements that correct the shape of the pulse.
As a result, the thyristor periodically turns on / off. Capacitor C2 is discharged to the primary winding of the high voltage transformer.
High-voltage pulse generator, fig. 11.18, contains a unijunction transistor-based generator as a control element.
Rice. 11.18. Scheme of a high-voltage pulse generator with a control element on a unijunction transistor.
The mains voltage is rectified by a diode bridge VD1 VD4. The ripple of the rectified voltage is smoothed out by the capacitor C1, the capacitor charge current at the moment the device is connected to the network is limited by the resistor R1. Capacitor C3 is charged through resistor R4. At the same time, a pulse generator on a unijunction transistor VT1 comes into action. Its "trigger" capacitor C2 is charged through resistors R3 and R6 from a parametric stabilizer (ballast resistor R2 and zener diodes VD5, VD6). As soon as the voltage on the capacitor C2 reaches a certain value, the transistor VT1 switches, and an opening pulse is sent to the control transition of the thyristor VS1.
The capacitor C3 is discharged through the thyristor VS1 to the primary winding of the transformer T1. A high voltage pulse is formed on its secondary winding. The repetition rate of these pulses is determined by the frequency of the generator, which, in turn, depends on the parameters of the chain R3, R6 and C2. With a trimmer resistor R6, you can change the output voltage of the generator by about 1.5 times. In this case, the pulse frequency is regulated within 250 ... 1000 Hz. In addition, the output voltage changes when the resistor R4 is selected (in the range from 5 to 30 kOhm).
It is desirable to use paper capacitors (C1 and SZ for a rated voltage of at least 400 V); the diode bridge must be designed for the same voltage. Instead of what is indicated on the diagram, you can use the thyristor T10-50 or, in extreme cases, KU202N. Zener diodes VD5, VD6 should provide a total stabilization voltage of about 18 V.
The transformer is made on the basis of TVS-110P2 from black and white TVs. All primary windings are removed and 70 turns of PEL or PEV wire with a diameter of 0.5 ... 0.8 mm are wound onto the vacated space.
The electrical circuit of the high voltage pulse generator, fig. 11.19, consists of a diode-capacitor voltage multiplier (diodes VD1, VD2, capacitors C1 C4). Its output is a constant voltage of approximately 600 V.
Rice. 11.19. Scheme of a high-voltage pulse generator with a mains voltage doubler and a trigger pulse generator based on a unijunction transistor.
A single-junction transistor VT1 of the KT117A type was used as the threshold element of the device. The voltage at one of its bases is stabilized by a parametric stabilizer on a VD3 zener diode of the KS515A type (stabilization voltage 15 B). Capacitor C5 is charged through resistor R4, and when the voltage at the control electrode of transistor VT1 exceeds the voltage at its base, VT1 will switch to a conducting state, and capacitor C5 will be discharged to the control electrode of thyristor VS1.
When the thyristor is turned on, the chain of capacitors C1 C4, charged to a voltage of about 600 ... 620 V, is discharged to the low-voltage winding of the step-up transformer T1. After that, the thyristor is turned off, the charge-discharge processes are repeated at a frequency determined by the constant R4C5. Resistor R2 limits the short circuit current when the thyristor is turned on and at the same time is an element of the charging circuit of capacitors C1 C4.
The converter circuit (Fig. 11.20) and its simplified version (Fig. 11.21) is divided into the following nodes: network surge filter (noise filter); electronic regulator; high voltage transformer.
Rice. 11.20. The electrical circuit of the high voltage generator with a surge protector.
Rice. 11.21. The electrical circuit of the high voltage generator with a surge protector.
The scheme in fig. 11.20 works as follows. Capacitor SZ is charged through a diode rectifier VD1 and resistor R2 to the peak value of the mains voltage (310 V). This voltage enters through the primary winding of the transformer T1 to the anode of the thyristor VS1. On the other branch (R1, VD2 and C2), capacitor C2 is slowly charged. When, during its charging, the breakdown voltage of the VD4 dinistor is reached (within 25 ... 35 V), the capacitor C2 is discharged through the control electrode of the thyristor VS1 and opens it.
Capacitor C3 is almost instantly discharged through an open thyristor VS1 and the primary winding of transformer T1. The pulsed alternating current induces a high voltage in the secondary winding T1, the value of which can exceed 10 kV. After the discharge of the capacitor C3, the thyristor VS1 closes, and the process is repeated.
A television transformer is used as a high-voltage transformer, in which the primary winding is removed. For the new primary winding, a winding wire with a diameter of 0.8 mm is used. Number of turns 25.
For the manufacture of inductors of the barrier filter L1, L2, high-frequency ferrite cores are best suited, for example, 600НН with a diameter of 8 mm and a length of 20 mm, having approximately 20 turns of a winding wire with a diameter of 0.6 ... 0.8 mm.
Rice. 11.22. The electrical circuit of a two-stage high voltage generator with a control element on a field-effect transistor.
A two-stage high voltage generator (author Andres Estaban de la Plaza) contains a transformer pulse generator, a rectifier, a timing RC circuit, a key element on a thyristor (triac), a high-voltage resonant transformer and a thyristor operation control circuit (Fig. 11.22).
Analogue of the transistor TIP41 KT819A.
A low-voltage transformer voltage converter with cross-feedback, assembled on transistors VT1 and VT2, generates pulses with a repetition rate of 850 Hz. Transistors VT1 and VT2 are mounted on radiators made of copper or aluminum to facilitate operation when high currents flow.
The output voltage taken from the secondary winding of the transformer T1 of the low-voltage converter is rectified by the diode bridge VD1 VD4 and charges the capacitors C3 and C4 through the resistor R5.
The thyristor turn-on threshold is controlled by a voltage regulator, which includes a VTZ field-effect transistor.
Further, the operation of the converter does not differ significantly from the processes described earlier: there is a periodic charge / discharge of capacitors on the low-voltage winding of the transformer, damped electrical oscillations are generated. The output voltage of the converter when using the ignition coil from the car as a step-up transformer at the output reaches 40 ... 60 kV at a resonant frequency of about 5 kHz.
Transformer T1 (output flyback transformer) contains 2x50 turns of wire with a diameter of 1.0 mm, wound bifilar. The secondary winding contains 1000 turns with a diameter of 0.20 ... 0.32 mm.
Note that modern bipolar and field-effect transistors can be used as controlled key elements.
HV blocking generator (high voltage power supply) for experiments - you can buy it on the Internet or make it yourself. To do this, we need not a lot of details and the ability to work with a soldering iron.
In order to collect it you need:
1. Horizontal scan transformer TVS-110L, TVS-110PTs15 from tube b/w and color TVs (any line)
2. 1 or 2 capacitors 16-50v - 2000-2200pF
3. 2 resistors 27Ω and 270-240Ω
4. 1-transistor 2T808A KT808 KT808A or similar in characteristics. + good heatsink for cooling
5. Wires
6. Soldering iron
7. Straight arms
And so we take the lineman, disassemble it carefully, leave the secondary high-voltage winding, consisting of many turns of thin wire, a ferrite core. We wind our windings with enameled copper wire on the second free side of the ferite core, having previously made a tube around the ferite from thick cardboard.
First: 5 turns approximately 1.5-1.7 mm in diameter
Second: 3 turns approximately 1.1mm in diameter
In general, the thickness and number of turns can be varied. What was at hand - from that and made.
Resistors and a pair of powerful bipolar n-p-n transistors, KT808a and 2t808a, were found in the pantry. He did not want to make a radiator - due to the large size of the transistor, although later experience showed that a large radiator is definitely needed.
To power all this, I chose a 12V transformer, you can also power it from a regular 12 volt 7A acc. from UPS-a. (to increase the voltage at the output, you can apply not 12 volts, but for example 40 volts, but here you already need to think about good cooling of the trance, and turns of the primary winding can be made not 5-3 but 7-5 for example).
If you are going to use a transformer, you will need a diode bridge to rectify the current from AC to DC, the diode bridge can be found in the power supply from the computer, you can also find capacitors and resistors + wires there.
as a result, we get 9-10kV at the output.
I placed the whole structure in the case from the PSU. it turned out pretty compact.
So, we have an HV Blocking Generator which allows us to experiment and run the Tesla Transformer.
Powerful high voltage generator (Kirlian apparatus), 220/40000 volts
The generator generates voltages up to 40,000 V and even higher, which can be applied to the electrodes described in previous projects.
It may be necessary to use a thicker glass or plastic plate in the electrode to avoid serious electrical shock. Although the circuit is quite powerful, its output current is low, which reduces the risk of a fatal blow if it comes into contact with any parts of the device.
However, you should be extremely careful when handling it, as the possibility of electric shock is still possible.
Attention! High voltages are dangerous. Be extremely careful when working with this circuit. It is desirable to have experience with such devices.
You can use the generator in experiments with Kirlian photography (electrophotography) and other paranormal experiments, such as those related to plasma or ionization.
The circuit uses conventional components, its output power is about 20 watts.
Below are some specifications of the device:
- power supply voltage - 117 V or 220/240 V (AC mains);
- output voltage - up to 40 kV (depending on the high-voltage transformer);
- output power - from 5 to 25 W (depending on the components used);
- number of transistors - 1;
- operating frequency - from 2 to 15 kHz.
Principle of operation
The scheme shown in fig. 2.63, consists of a single-transistor generator, the operating frequency of which is determined by the capacitors C3 and C4 and the inductance of the primary winding of the high-voltage transformer.
Rice. 2.63 Kirlian apparatus
The project uses a powerful silicon n-p-n transistor. To remove heat, it should be mounted on a sufficiently large radiator.
Resistors R1 and R2 determine the output power by setting the current of the transistor. Its operating point is set by the resistor R3. Depending on the characteristics of the transistor, it is necessary to experimentally select the value of the resistor R3 (it should be in the range of 270 ... 470 Ohms).
As a high-voltage transformer, which also determines the operating frequency, the horizontal scan output transformer of the TV (linear transformer) with a ferrite core is used. The primary winding consists of 20 ... 40 turns of conventional insulated wire. A very high voltage is generated on the secondary winding, which you will use in experiments.
The power supply is very simple, it is a full-wave rectifier with a step-down transformer. It is recommended to use a transformer with secondary windings providing voltage 20...25 V and currents 3...5 A.
Assembly
The list of elements is given in table. 2.13. Since the assembly requirements are not very strict, in Fig. 2.64 shows the mounting method using a mounting block. It houses small parts, such as resistors and capacitors, interconnected by surface mounting.
Table 2.13. Item List
Large parts, such as a transformer, are screwed directly to the housing.
The case is better to make plastic or wood.
Rice. 2.64. Mounting the device
The high voltage transformer can be removed from a black and white or color TV that is not working. If possible, use a TV with a diagonal of 21 inches or more: the larger the kinescope, the more voltage the line transformer of the TV should generate.
Resistors R1 and R2 - wire-wound C1 - any capacitor with a rating of 1500 ... 4700 uF.
Many of us at least once in our lives have seen photos of high-voltage generators on the Internet or in real life, or made them ourselves. Many circuits presented on the Internet are quite powerful, their output voltage is from 50 to 100 kilovolts. Power, as well as voltage, is also quite high. But their food is the main problem. The voltage source must be suitable for the power generator, must be able to give a long-term high current.
There are 2 power supply options for HV generators:
1) battery,
2) mains power supply.
The first option allows you to start the device far "from the outlet". However, as noted earlier, the device will consume a lot of power and therefore the battery must provide this power (if you want the generator to work "at 100"). Batteries of such power are quite large and you can’t call an autonomous device with such a battery. If you supply power from a mains source, then you don’t have to talk about autonomy either, since the generator literally “you can’t tear it off the outlet”.
My device is quite autonomous, as it consumes not so much from the built-in battery, however, due to low consumption, the power is also not high - about 10-15W. But you can get an arc from a transformer, the voltage is about 1 kilovolt. From the voltage multiplier up - 10-15 kV.
Closer to design...
Since this generator was not planned for serious purposes, I placed all its “insides” in a cardboard box (no matter how ridiculous it may sound, but it is. I ask you not to judge my design strictly, since I am not a specialist in high-voltage technology L). My device has 2 Li-ion batteries with a capacity of 2200 mAh. They are charged using an 8 volt linear regulator: L7808. It is also in the body. There are also two chargers: from the mains (12 V, 1250 mAh) and from the car's cigarette lighter.
The high voltage generation circuit itself consists of several parts:
1) input voltage filter,
2) a master oscillator built on a multivibrator,
3) power transistors,
4) a high-voltage step-up transformer (I want to note that the core should not have a gap, the presence of a gap leads to an increase in current consumption and, as a result, failure of power transistors).
You can also connect a "symmetrical" voltage multiplier or ... a fluorescent lamp to the high-voltage output, then the HV generator turns into a flashlight. Although, in fact, this device was originally planned to be made as a flashlight. The converter circuit is made on a breadboard, if you wish, you can create a printed circuit board. The maximum consumption of the circuit is up to 2-3 Amperes, this should be taken into account when choosing switches. The cost of the device depends on where you took the components. I found most of the complete set in my box or in a box for storing radio components. I only had to buy a linear stabilizer L7808, IVLM1-1/7 (actually I inserted it here for the sake of interest, but I bought it out of curiosity J), I also had to buy an electronic transformer for halogen lamps (I took only a transformer from it). The wire for winding the secondary (step-up, high-voltage) winding was taken from a long-burned line transformer (TVS110PTs), and I advise you to do the same. So the wire in line transformers is high-voltage and there should be no problems with insulation breakdown. We seem to have figured out the theory - now let's move on to practice ...
Appearance…
Fig.1 - view of the control panel:
1) health indicators
2) Charging voltage presence indicator
3) input from 8 to 25 volts (for charging)
4) button to turn on the battery charge (turn on only when the charger is connected)
5) battery switch (upper position - main, lower - spare)
6) HV generator switch
7)high voltage output
There are 3 health indicators on the front panel. There are so many of them here, because the seven-segment indicator is my initial (the first letter of my name is on it: “A” J), the LEDs above the switch and switch were originally planned to be additional indicators of battery charge, but there was a problem with the display circuit, and the holes in the case were already made. I had to put LEDs, but already as just indicators, so as not to spoil the appearance.
Fig. 2 - view of the voltmeter and indicator:
8) voltmeter - shows the voltage on the battery
9) indicator - IVLM1-1/7
10) fuse (against accidental activation)
I installed the vacuum fluorescent indicator for the sake of interest, since this is my first indicator of this type.
Fig. 3 - internal view:
11)body
12) batteries (12.1-main, 12.2-spare)
13) linear stabilizer 7808 (for charging batteries)
14)converter board
15) heat sink with field effect transistor KP813A2
Here, I think there is nothing to explain.
Fig. 4 - chargers:
16) from a network of 220 v. (12 V., 1250 mA.)
17) from car cigarette lighter
Fig.5 - loads for AVVG:
18)9 WFluorescent Lamp
19) "symmetrical" voltage multiplier
Fig.6 - schematic diagram:
USB1 - standard outputUSB
BAT1, 2 – Li- ion7.4 in. 2200 mAh (18650 X 2)
R1, 2, 3, 4 - 820 Ohm
R5 - 100 kOhm
R6, 7 - 8.2 ohm
R8 - 150 Ohm
R9, 12 - 510 Ohm
R10, 11 - 1 kΩ
L1 - core from a choke from an energy-saving lamp, 10 turns of 1.5 mm.
C1 - 470uF 16V
C2, 3 - 1000 uF 16 in.
C4, 5 - 47 nF 250 V.
C6 - 3.2 nF 1.25 kV
C7 - 300 pF 1.6 Kv.
C8 - 470 pF 3 Kv.
C9, 10 - 6.3 nF
C11, 12, 13, 14 - 2200 pF 5 kv.
D1 - red LED
D2 - AL307EM
D3 - ALS307VM
VD1, 2, 3, 4 - KTs106G
HL1 - ZLS338B1
HL2 – NE2
HL3 - IVLM1-1/7
HL4 - LDS 9W
IC1 – L7808
SB1 - button 1A
SA1 - switch 3A (ON- OFFwith neon lamp)
SA2 - switch 6A (ON- ON)
SA3 - switch 1A (ON- OFF)
PV1 -M2003-1
T1 - step-up transformer:
BB winding: 372 turns PEV-2 0.14mm. R=38.6ohm
Primary winding: 2 to 7 turns of PEV-… 1mm. R=0.4ohm
VT1 - KT819VM
VT2 - KP813A2
VT3, 4 - KT817B
Total number of components: 53.
Without which this circuit MAY work, in fact there are many without: IC1, R1, 2, 3, 4, 5, 8, C1, 2, 3, 4, 5, 7, 8,
Explanations for the scheme:
The minus is common, it goes from the USB input to the converter board. The pluses from the batteries go to the switch, from it there is already one output to the switch (SA1), and from it to the converter. Also, the plus goes to the voltmeter (PV1), through the resistor to the indicator cathode and to the anodes of the LEDs (a separate resistor for each LED). Charging is carried out after a voltage of 8 to 25 volts is applied to the USB input, and also after pressing the button (SB1), the LED (D1) lights up after the voltage for charging is applied (you can control the charging process using a PV1 voltmeter).
Switching between the main and spare batteries is carried out using the switch (SA1), then the power plus goes to the switch (SA2) (through the SA3 switch) of the HV generator, the neon lamp (HL2) is inside the switch. Further, the power outputs go to the block of capacitors and the master oscillator built on a multivibrator (VT3, 4. C9, 10. R9, 10, 11, 12), the KT817B transistors can be replaced with any other analogs, from it the pulses go to the base and gate of the transistors (VT1, VT2), transistors can be used less or more powerful analogs. Field and bipolar transistors are used here, this is done in order to reduce consumption. After the transformer, high voltage is supplied to the group of anode segments of the vacuum luminescent indicator, and then to the BB output.
Consumption (like a flashlight): in 1 minute, the circuit discharges the battery by 0.04 V. (40 millivolts.). If the generator runs for 25 minutes, then it will be discharged by 1 volt (25 * 0.04).
February 20, 2014 at 06:27 pmDangerous Fun: An Easy-to-Repeat High Voltage Generator
- DIY or DIY
- tutorial
Good afternoon, dear Khabrovites.
This post is going to be a little different.
In it, I will tell you how to make a simple and powerful enough high voltage generator (280,000 volts). As a basis, I took the scheme of the Marx Generator. The peculiarity of my circuit is that I recalculated it for affordable and inexpensive parts. In addition, the circuit itself is easy to repeat (it took me 15 minutes to assemble it), does not require configuration and starts the first time. In my opinion, it is much simpler than a Tesla transformer or a Cockcroft-Walton voltage multiplier.
Principle of operation
Immediately after switching on, the capacitors begin to charge. In my case, up to 35 kilovolts. As soon as the voltage reaches the breakdown threshold of one of the arresters, the capacitors through the arrester will be connected in series, which will double the voltage on the capacitors connected to this arrester. Because of this, the rest of the arresters almost instantly work, and the voltage across the capacitors adds up. I used 12 steps, that is, the voltage should be multiplied by 12 (12 x 35 = 420). 420 kilovolts are almost half a meter discharges. But in practice, taking into account all the losses, discharges 28 cm long were obtained. The losses were due to corona discharges.
About details:
The circuit itself is simple, consists of capacitors, resistors and arresters. You will also need a power source. Since all parts are high-voltage, the question arises, where can I get them? Now about everything in order:1 - resistors
We need resistors of 100 kOhm, 5 watts, 50,000 volts.I tried many factory resistors, but none could withstand such a voltage - the arc pierced over the case and nothing worked. Careful googling gave an unexpected answer: the craftsmen who built the Marx generator for voltages of more than 100,000 volts used complex liquid resistors, the Marx generator with liquid resistors, or used a lot of steps. I wanted something simpler and made the resistors out of wood.
I broke off two even branches of a damp tree on the street (dry current does not conduct) and turned on the first branch instead of a group of resistors to the right of the capacitors, the second branch instead of a group of resistors to the left of the capacitors. It turned out two branches with many conclusions at equal distances. I drew conclusions by winding bare wire over the branches. Experience shows that such resistors withstand voltages of tens of megavolts (10,000,000 volts)
2 - capacitors
Everything is easier here. I took capacitors that were the cheapest on the radio market - K15-4, 470 pf, 30 kV, (they are also greensheets). They were used in tube TVs, so now you can buy them at disassembly or ask for free. They withstand a voltage of 35 kilovolts well, not a single one has broken through.3 - power supply
To assemble a separate circuit to power my Marx generator, my hand simply did not rise. Because the other day a neighbor gave me an old TV set "Electron TTs-451". At the anode of the kinescope in color televisions, a constant voltage of about 27,000 volts is used. I disconnected the high-voltage wire (suction cup) from the kinescope anode and decided to check what kind of arc would come from this voltage.Having played enough with the arc, I came to the conclusion that the circuit in the TV is quite stable, easily withstands overloads, and in the event of a short circuit, protection is triggered and nothing burns out. The circuit in the TV has a power reserve and I managed to overclock it from 27 to 35 kilovolts. To do this, I twisted the R2 trimmer in the TV power supply module so that the horizontal power supply rose from 125 to 150 volts, which in turn led to an increase in the anode voltage to 35 kilovolts. When you try to increase the voltage even more, it breaks the KT838A transistor in the line scan of the TV, so you need not to overdo it.
Assembly process
Using copper wire, I screwed the capacitors to the tree branches. There must be a distance of 37 mm between the capacitors, otherwise unwanted breakdown may occur. I bent the free ends of the wire so that between them it turned out 30 mm - these will be the arresters.It is better to see once than to hear 100 times. Watch the video where I showed in detail the assembly process and the operation of the generator:
Safety
Special care must be taken, as the circuit operates on a constant voltage and a discharge from even a single capacitor is likely to be fatal. When turning on the circuit, you need to be at a sufficient distance because electricity breaks through the air 20 cm or even more. After each shutdown, it is imperative to discharge all capacitors (even those on the TV) with a well-grounded wire.It is better to remove all electronics from the room where the experiments will be carried out. Discharges create powerful electromagnetic impulses. The phone, keyboard and monitor that I have shown in the video are out of order and can no longer be repaired! Even in the next room, my gas boiler turned off.
You need to protect your hearing. The noise from the discharges is similar to shots, then it rings in the ears.
The first thing you feel when you turn it on is how the air in the room is electrified. The intensity of the electric field is so high that it is felt by every hair of the body.
The corona discharge is clearly visible. Beautiful bluish glow around parts and wires.
Constantly slightly shocked, sometimes you don’t even understand why: touched the door - a spark slipped through, wanted to take the scissors - shot from the scissors. In the dark, I noticed that sparks jumped between different metal objects that were not connected with the generator: in a diplomat with a tool, sparks jumped between screwdrivers, pliers, and a soldering iron.
Light bulbs light up on their own, without wires.
Ozone smells throughout the house, like after a thunderstorm.
Conclusion
All parts will cost about 50 UAH ($ 5), this is an old TV and capacitors. Now I am developing a fundamentally new scheme, with the goal of obtaining meter discharges without any special costs. You ask: what is the application of this scheme? I will answer that there are applications, but they need to be discussed in another topic.That's all for me, be careful when working with high voltage.
