The circuit shown is from the 1977 GE semiconductor manual. More modern equivalent SCRs can be used. R1 must be wire type.
The frequency of this clock oscillator is given by the crystal. The trimmer sets the ideal...
We found this circuit in a documentation from the 90s. It is a simple test for NPN and PNP...
We found this micro amplifier in a technical documentation from National Semiconductor. The...