Noise generator (T467E)

Found in a 1948 MIT publication, this noise generator is intended for testing amplifiers of the time. The VR105 is a voltage regulating tube.

Fish Attractor (CB425E)
The tone produced by this circuit attract fishes. The circuit is installed into a small can and...
1 kHz Multivibrator (CB486)
A square signal of about 1 kHz is produced by this astable multivibrator. Frequency is determined...
Electronic Thermometer (CB4306E)
This bargraph-type circuit employs a not very common integrated circuit today, but can be adapted...