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.
We found this antenna amplifier or Booster circuit in an Electronics Now from the 90s. The circuit...
We found this circuit in the Linear Applications Handbook of the 1994 National Semiconductor. The...
This circuit is from a 1976 Motorola power semiconductor manual. In it we have the optical...