Found in 1980s documentation, this circuit indicates the phase of a three-phase signal from the power grid. The neon lamp is common.
This high speed laser diode driver was found in a 1980s documentation. Power FETs can be replaced...
This circuit is from an old publication about transistors, using types of germanium that are no...
This circuit uses an LDR as a sensor to trigger an LED indicator at a preset lighting level. The...