This circuit was obtained from a National Semiconductor manual from the 1990s. The circuit employs a pair of matched transistors, and the indicator is analog.
November 2016 - Texas Instruments' new TLV8802 nano-power operational amplifiers for wireless...
This sophisticated photometer that has a light comparator with LED indicator came out in an...
This is a version of the previous circuit that includes a tone modulator based on a Hartley...