This circuit is from old documentation, but it can be implemented with modern transistors such as 2N2222 for bipolar and BF124 for FET. The crystal determines the operating frequency.
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...