This circuit with an unusual configuration was found in the January 1974 issue of Radio Electronics magazine. The frequency is given by L1/C1, and the transistors admit equivalents.
This circuit, obtained from old documentation, allows the recovery of sulfated batteries. The...
This 80's circuit uses a small light bulb as an indicator, but an LED with the appropriate resistor...
This amplifier with the RCA CA3018 integrated circuit was found in the August 1970 issue of Radio...