Two-tube regenerative receiver (T1595E)

This circuit is from a Radio Electronics from 1949. The circuit is battery powered and has high impedance listening.

Old Transistorized Amplifier (CB18332E)
This amplifier with a few watts of power was found in a Japanese technical documentation from the...
Operational Constant Current Source (CB13407E)
This circuit is from a 1977 National Semiconductor integrated circuits manual. The circuit admits...
12 V x 5A power supply (CB17051E)
This conventional power supply uses discrete components and can provide 12 V or 13.6 V output with...