Using an analog microamperimeter this circuit has a phototransistor adapted to the wheel as a sensor. The circuit is from American documentation from the 1980s, but the components are common today.
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...