HV inverter parts list

HV Inverter Parts List

None of the component values are critical. It is quite likely that everything needed is already patiently waiting in your junkbox. If not, except for the flyback, most if not all of the parts should be available from Radio Shack. See the section: "Low voltage power supply" for a simple design to use with this inverter.

Some experimenting with different value resistors and even the number of turns on each winding may improve performance for your particular flyback.

• Q1, Q2 - 2N3055 or similar NPN power transistors (reverse polarity of Vcc if using PNP transistors.) Maximum stress on transistors are about 2 to 3 times VCC. Heat sinks will be needed for continuous operation.
• R1 - 110 ohms, 2 W resistor (5 W for Vcc of 24 V). This provides base current to get circuit started.
• R2 - 27 ohms, 5W resistor. This provides return path for base feedback during operation.
• T1 - Flyback transformer from/for B/W TV, video display terminal, color TV, computer monitor, etc., modified according to text above.

Most modern flybacks include built-in HV rectifier diode(s) and/or voltage multiplier (tripler) so output without additional components will be high voltage positive or somewhat smoothed HV DC.

Note: this kind of flyback transformer drives the CRT directly and uses its glass envelope as the main high voltage filter capacitor. (A foot square piece of 1/8 inch Plexiglas with Aluminum foil plates makes an filter capacitor.)

• Wire - a couple of feet of #16-#20 hookup wire, magnet wire, or any other insulated wire for home made primaries. Use electrical tape to fix windings to core. Wind feedback winding on top of drive winding.