This circuit is from American documentation from the 1980s. The transistors are general purpose types and the relay can be 6 or 12 V depending on the supply voltage.
This circuit generates 50, 100 and 200 Hz signals from a 2.2768 MHz TV crystal. The circuit can be...
This small power amplifier makes use of an output transformer given its design time. In fact, the...
This resistance meter with the CA3130 was found in an English publication from 1977. The circuit has...