This circuit makes use of a 741 single source operational amplifier to measure resistors on a linear scale. The circuit may use as an indicator a common multimeter on a low current range.
This is an old test circuit for integrated TTL counters, feeding a Nixie tube, common at the time....
This traditional crystal radio circuit, but which has a modern version with diode, was found in an...
This headphone amplifier using a pickup coil can be used as an extension for devices such as TVs,...