The circuit is from 1968, but we can use a modern one like the 741. The symmetrical power supply voltage (two batteries or source) can be from 9 to 12 V.
This circuit was found in a Popular Electronics from the 90s. The frequency is given by R2 and C1....
High performance 16 A Buck regulators capable of operating at 2.7 to 4.8 V voltages and 0.25 to...
This configuration triggers an external circuit or simply an LED for time given by R1 and C1 (T =...