This test circuit was found in the PE Hobbyst Handbook in a 1990s edition. The circuit tests the battery under load. The load, as the battery is selected by the switch.
This simple circuit controls the brightness of an LED from LDRs, NTCs, PTCs or other resistive sensors....
This remote listening device was found in documentation from the 50's. The transistors used are...
This circuit came out in a Modern Electronics from June 1990. In it we have a low frequency...