This circuit identifies the polarity of DC signals and if the signal is AC. The circuit is from 1969 US EDN documentation. Operational may be equivalent.
This amplifier uses a 1975 integrated circuit, which is uncommon today. The circuit has a gain of 30...
Using junction FETs, a configurable configuration is achieved for very low frequencies. FETs can...
This 2-terminal regulator was obtained from a 1990s National Semiconductor manual. The components admit...