This circuit for currents from 500 mA to 1.5 A was found on a Ham Radio from the 90s. R4 determines the current in the load under test. Transistors must be equipped with radiators.
This is stage is transformer coupled and was found in na old publication of the year 1958. The...
This circuit is from the magazine 73, for radio amateurs, from the 80s. The circuit uses common...
This indicator circuit used and game machines (arcades) to indicate that the machine is being...