This circuit was obtained in documentation from the 1980s. The triac and the unijunction support modern equivalents. The trigger transformer is 1: 1 turn ratio.
The sensors in this circuit, found in a 1999 documentation, are stripped wire tips at different levels...
This traditional crystal oscillator configuration can use any CMOS gate configured as an inverter. R1...
This amplification stage circuit with a germanium transistor was found in a 1980s documentation. The...