This commercial receiver from the year 1958 uses two AA cells as Power supply. The circuit is intend to receive MW station and the transistors are germanium types not easy to find today.
This sensitive amplifier for low current measurement uses a differential amplifier configuration with...
The circuit bellow shows how four inverters [NAND, NOR or Inverters] Kim - This could be NAND,...
The Texas Instruments OPAx145 Series of Operational Amplifiers is available from Mouser...