This circuit was found in a Popular Electronics from the 90s. It is based on components still common today and an optical coupler for the triac. The sensor is a thermistor.
The circuit shown in the figure consists of a 200mA low voltage drop (LDO) regulator using the...
Depending on the value of C1, this oscillator can produce signals of up to 1 MHz. For a capacitor of 10...
This electronic Morse key was found in a Popular Electronics from the 90's. The components are common,...