This circuit was obtained from an American 1980s documentation. The frequency depends on the crystal and the circuit may be a PNP that reaches the generated frequency.
This circuit was obtained in a 1976 magazine. We can use the 555 and another BC548 to generate square...
This 1969 Electronics World power supply has 5 V to power digital circuits and a 170 V output for...
This amplifier uses common transistors in a phase inverter configuration. Transistors must be...