This variable oscillator with power step for alarms was found in an American documentation from the 90's. The power transistor must be equipped with a heat sink.
This circuit monitors the temperature of soldering irons, taking them when necessary to a low...
The traditional circuit was taken from a French magazine Radio Plans that no longer exists but can...
In this circuit the CA3140, an operational amplifier, is used as a comparator with the zener diode...