This circuit operates with an AM radio tuned to or near 900 kHz if there is a station at this location. The coil consists of 60 + 40 turns 28 on a ferrite rod.
This circuit sensor is an NTC with a resistance of the order of 2k. The SCR can be from the TIC...
The load current can be adjusted up to about 1 A. The transistor can be TIP32 or TIP42. The...
This oscillator with common general-purpose transistors appeared in Radio Electronics magazine in...