This is an old test circuit for integrated TTL counters, feeding a Nixie tube, common at the time. The circuit is from the 90's, not being given the power supply.
This powerful amplifier with 2N3055 transistors at the output provides a few tens of watts rms on a...
With this circuit it is possible to receive and send audio signals simultaneously over the same...
This circuit generates 100 MHz signals from a 20 kHz crystal. The circuit is from an 80's...