1pcs High Voltage DC-DC Boost Converter 5V-12V Step up to 300V-1200V Power Module

Bought one of these for product evaluation for energizing Giger-Muller tubes which it can easily produce voltages up to 1500 volts but as delivered its operation is unstable.I traced out the circuitry and found the designer made a design error and did not decouple the power pin of the 555 Timer chip. This component is required to produce stable operation of the 555 Timer chip and is so noted in the manufactures data sheet.Problem is resolved by installing a 10 uF, 50 Volt electrolytic capacitor across the power rails on the PCB board as shown in the attached picture, there are two plated through holes that can be used for the capacitor leads, pay attention to polarity when installing the capacitor.After modification the "board" operated stability producing 900 volts with 4.5 volts applied and drawing less than 16 mA. Note: The on board adjustment trimmer controls the "frequency" of the 555 Timer, the adjustment is dependent on the applied voltage and should be adjusted from the lowest setting (fully clockwise) upward in frequency until the need voltage is reached.

Big thanks to the other reviewer that recommended adding the 50v 10uf capacitor across the input. One through hole is almost under the leg of another component but it is possible.I used it to reform an old 4uf 600V capacitor from the 50s that is no longer available.I would give it 5 stars if I didn't have to add the capacitor.I ran it about 24 hours at 600V so it seems reliable.

Impossible to know if it's working if you don't have a volt meter. The tuning potentiometer doesn't produce an output when fully CW or CCW. If you assume that a small increase CW increases the output, you are mistaking. The RED LED just tells you the input power is there. Finally when you get it at 1000Volt, the capacitors are so small that you can hold the wires in your hands. Don't buy it !!!

This little circuit is as basic as can be, but it does what it's supposed to. I can adjust it to my required voltage (900 volts) and it's reasonably stable if the input voltage is well regulated and it has a constant load. It is noisy and can use a bit of output filtering in sensitive applications. The most serious problem is the noise it injects into the low voltage supply. Than definitely will need to be addressed in my application. Because of its poor load regulation setting the output voltage requires a very high impedance meter - preferably an electrostatic meter. Your VOM or VTVM is not going to cut it.

This unit seems like it will work for my project, which is a geiger tube power supply. Output is about 315 to 590V with 5V input, about 375 to 715V with 6V input (*), and the 3/4 turn trim pot is very crude adjustment, so your project might require regulation. It stops producing HV when the pot is rotated near its CCW stop, so be careful. Can't tell how much current it can deliver, I would guess no more than 10 ma.(*) My measuring equipment was a cheap digital voltmeter with supposedly constant input impedance, measuring a 30:1 voltage divider, so these values are approximate.