This circuit activates a relay after a time given by C1 and R1. The circuit is from a Radio Electronics from December 1974. The relay voltage is the same as that used in the power supply.
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...