This timer, like the previous circuits, uses a currently uncommon integrated circuit. The time is given by capacitor C1 and R2 which has the range of values indicated in the diagram.
This circuit was obtained from a Radio Electronics in May 1967. The circuit consists of a system...
This simple two-transistor capacitance meter uses a 50 uA microammeter as an indicator instrument. The...
Found in a European magazine from the 90s, this circuit emits beeps that are several seconds apart to...