Found in a European magazine from the 90s, this circuit emits beeps that are several seconds apart to indicate that a device is on. The transducer is a ceramic or crystal capsule.
Found in Mullard's 1960s transistor manual, this circuit has components that depend on the...
In this transmitter for telephone conversations, found in a 1985 publication, the L1 coil has 4...
This 1 kW circuit was found in documentation from the 90s. The sensor is a thermistor, and the...