This circuit was obtained in an Electronics Now from the 90s. The circuit uses operational amplifiers from the time and the indicator is of the Sonalert type with internal oscillator.
This circuit consists of a single Hartley oscillator using a bipolar transistor that can generate...
We found this circuit in a documentation about SCRs from the 70s. The circuit can be implemented with a...
This circuit was obtained in an old documentation, making use of an operational amplifier of the...