This circuit is from a 90s Radio Electronics. The resistors must be precision types and the transistor is a general-purpose type. The operational admits equivalent.
This circuit is from the 1974 Motorola Unijunction Trigger Circuits for Gated Thyristor. The triac...
Found in old American documentation, this circuit can divide the frequency of a signal by 2 or 3...
This transceiver is also low power, but this time, it can generate signals in the 144 MHz band. In the...