Low noise amplifier (T466E)

Found in 1948 MIT documentation, this 4-tube amplifier is characterized by its low noise level.

3 to 20 MHz XTAL Oscillator (CB13870E)
We found this oscillator in a publication for radio amateurs from the 70s. The circuit generates...
Instrumentation amplifier (CB20685E)
This low displacement circuit was found in American documentation from the 90s. Operational...
OCV-based Battery Charge Meter (CB15596E)
The circuit shown in the figure was suggested by Maxim (www.maxim-ic.com) based on the DS2786B...