Equivalent transistors can be used in this circuit for automotive applications in the 1980s. The frequency is given by the capacitor and the current of the lamp depends on the LM195 transistor.
Found in Popular Electronics this circuit will trigger a buzzer if the ignition key is removed...
Found in Popular Electronics, this sophisticated short-wave receiver requires a lot of skill from...
This circuit is from an old American documentation using LEDs in the rectification. The circuit...