Found in old documentation, this circuit can use modern equivalent components. The signal has good strength thanks to the use of a power transistor. The Q1 transistor is a unijunction of the time.
This metal detector was found in a 2001 Poptronics, but it can still be easily assembled, as the...
This circuit for 6 lamps was found in old American documentation. The supply is of high voltage...
With this circuit it is possible to have a safe indication of the balance point for the signals of the...