This humidity sensor indicates the different levels of conduction of the sensors through an LED bar. The circuit is from Popular Electronics and must be powered by cells or battery.
This small MW transmitter emits its signals at a distance of a few tens of meters, depending on the...
Found in a 90s 303 Circuits, this circuit has an output power of 100 mW. L1 consists of 890 turns...
The coil and sockets of this circuit found in a QST depend on the frequency band that is intended...