single cell dc/dc converter PCB BC327 PNP

this is a dc/dc converter PCB I designed a few years ago. One transistor, two coils, and some passive components. It is adjustable. prototype photo actual PCBs are infrared soldered. New revision of the dc/dc converter PCB! It has been tested from 1.2 volts to 5 volts input range. Small PIC circuits can be powered directly from 1.2 volts battery with … Continue reading

FM transmitters

Two FM transmitters were built recently. The first transmitter is based on 7 2n3904 transistors: The second transmitter is based on 3 2sc1740 transistors: Some resistors were made adjustable especially the emitter resistor and the bias resistors. Using other transistors than the originally suggested 2n3904, this is absolutely neccessary. The schematic for the second transmitter:

transistor tester

figured out I need one, to test high-voltage transistors from CFLs, that I want to use for radiation counter. For the PNP I use dc/dc converter PCB, for the NPN I simply rebuilt the circuit with reversed polarity. interestingly the NPN version actually has common ground, the PNP version does not. Also I figured out how to build it without … Continue reading

dc/dc converter, new PCB revision available

  redesigned the PCB! -no patches -high efficiency LED via 4.7k resistor -variable resistor to adjust quitescenct current -robust diode -imprint on the PCB for input/ouput, + and – this PCB can power small PIC circuits directly from 1.2 volts battery, as well it can replace 9v batteries, for instance it can generate small 12v currents from 2x AAA cells. … Continue reading