This high voltage source is formed by an inverter, around the transistor, which provides pulses of 150V to the inverter formed by the thyristor and capacitor in series with the transformer 2. This pulse output of 4.5kV to be multiplied with the network so as to achieve the output voltage of 13.5kV. Neon lamps (marked LN) form the thyristor triggering pulses.
This device allows up to 40,000 volts by 220V AC. The AC to AC Converter circuit is powered from the mains through primary transformer (220-24) to isolate the network while reducing the input voltage.
Here can be used as a fly-back transformer from a TV which is not used. Better to use a primitive type, without tripler or high voltage diode. This type of transformer is initially allowed to obtain ten thousand-volt voltage easily.
As shown in the Inverter circuit diagram obove , Its used as the oscillator stage astable multivibrator contained in IC1, a CMOS 4047 (this cult series 40xx series) by varying the resistance value of R1 trimmer (220 k total resistance) can vary the oscillation frequency of 40 Hz to 70 Hz square wave, phase shifted by 180 °, Output pin 10-11 will drives two NPN transistors TR1-TR3, which in turn is fed to the TR2-TR4.
How it work :
The master oscillator, a voltage reference and comparator collected on DA2. External elements DD1 and DD2 repeated internal structure of the TL494, in the part that works is unstable at low frequencies (false positive D-flip-flop).
Further, using the low-pass filter suppresses the upper harmonics of the PWM. LPF consists of two parts. First-DA1.1, with a smooth lowpass characteristic curves. Second-DA1.2 notch filter with a frequency of 150 Hz suppression. The analysis shows that the PWM contains only odd harmonics of the first and, because such a filter is enough to form a “beautiful” sine (oscillogram 2). And, as the level of the first harmonic is almost linearly dependent on porosity, we obtain a well-managed with precision sine constant component equal to 2.5 V. Further, in addition we get the inverse sine (Pin 14 DA1.4).
A simple scheme to generate the inverter voltage from 1.5V to 3V can be made on the basis of slightly modified the well-known multivibrator. Under these denominations in the scheme of the frequency converter is approximately 130 kHz. Inductance value can be calculated or chosen experimentally. But you can simply adjust the frequency of the converter to produce maximum output voltage. Schottky diode VD1 can be replaced by any other similar characteristics.