We found this circuit in the Linear Applications Handbook by National Semiconductor. It uses the LM3900, an operational transconductance amplifier as a base. Q1 can be a 2N2222 or similar.
This circuit uses integrated 555 and an amplification step with transistors, as we can see in the...
This circuit uses components that are still common despite being from 1995 documentation. The circuit can...
This circuit was obtained from American documentation from the 1990s. The transformer can be a car...