The circuit shown is from old English documentation and can be made with BC548 transistors for low power ones. The 2N3055 must be mounted on a heat radiator.
In the figure we have a practical circuit for use with a magnetic transducer. The 20 M ohms...
Based on the well-known LM3909, this LED pulser circuit was found in American documentation from...
This circuit was found in old documentation but uses components that are still common. The circuit...