This flasher circuit consists of an astable multivibrator with the frequencies given by the capacitors. The circuit is from 1965 using light bulbs, but LEDs can be used. Power comes from 4 batteries.
This circuit uses a contactor having been found in a 1987 publication. More modern equivalent...
This circuit for voltages up to about 20 V was found in a 90s Popular Electronics. The LED can be...
This small 3 transistor transmitter was found in an English publication from 1963. The coils must...