Review on 💡 Comidox 15KV Boost High Voltage Generator & Transformer Inverter Coil Module Disassembled Parts - DIY Kit (2 Sets with PCB Board) by Paul Lewis

Received my order for a 15kV high voltage generator from Comidox and assembled it the next day. It doesn't come with instructions but it's a very simple schematic and I've recreated the schematic from the supplied PCB and in addition I'll give some advice and comments on the design. The key to the device is a step-up transformer with a secondary winding of very thin wires that provides a high voltage output through the red and blue insulated wires. In addition to the primary coil there is a third winding of very thin magnet wire which is a feedback winding which serves as the input for the transistor oscillator (Q1) and is connected through a resistor R1 and a diode D1 to the base of the transistor. . The magnetic core is insulated throughout and before assembly and soldering, remove the insulation at the ends of the primary and return windings, wrap sandpaper or steel wool well so that the solder can adhere and make good contact. Another important step is the polarity of the feedback signal from the feedback coil (the coil with the thinnest wires to connect). be brought to high voltage. If that doesn't work, you may need to swap the connections to the feedback coil. How to know if it works? Electrocution is NOT a sure way to find out. I have an oscilloscope so I can build a simple 1000:1 or even 10,000:1 pull down resistor to reduce the voltage and observe the waveform at a safe level. Another option is to connect a miniature neon lamp in series with a 1MΩ resistor and see if the neon lamp lights up when connected to the red and blue output wires of the high voltage generator. If you listen well at high audio frequencies, I have found that the high voltage oscillator hums when working properly when assembled with the 120 ohm resistor for R1 that is included. I think this hum is caused by the fact that the iron frame of the transformer reacts mechanically to the alternating current to be generated. No hum might mean no AC power being generated, and you might need to swap the feedback coil leads. One last comment. For my application - protecting some plants from small predators - I didn't need 15kV, and even 1kV is more than enough, so I use a high voltage generator of only 3 volts powered by batteries and increase the base resistance R1 to 680 Ohm. reducing the base current by increasing R1 reduces the high voltage output power and also reduces the power consumption and heat generated by the high voltage generator circuit. It is safest to meet the minimum HV required for your application. Hope that helps.