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 RIAA equalizer preamp was found in a 1990s schematic. The transistors are an old version of...
This circuit uses two LEDs to indicate the state of a battery, the voltages at which they...
The bridge diodes of this circuit, found in a 1967 publication, are according to the motor...