The frequency of this Pierce oscillator, found in 1969 documentation, depends on the crystal. The current in the drain is about 500 uA. Crystals from other frequencies can be used.
Found in an Electronic Design from the 90's, this circuit uses common components. The circuit is...
When the sensor receives light, the relay closes its contacts and remains so even after the light...
This circuit produces pulses of 90 V at intervals that can reach 5 minutes. The circuit is from a...