Found in the May 1971 Radio Electronics magazine, this is the circuit for a commercial high-impedance instrument. The circuit uses 4 transistors and is powered by 2 9 V batteries.
May 2017 - Panasonic's new APS1 series of optical couplers with 3 750 V insulation and up to 50...
This circuit can detect both light and shadow using an LDR as a sensor. We found the circuit in an...
This simple megaphone is from old documentation, but uses still current components. The circuit is...