3-tube receiver 2 (T1603E)

Using known tubes, this receiver was found in a Radio Electronics from 1949. The circuit does not include the power supply.

Giro Counter (CB12052E)
This rev counter, which can be used in a car or engine, was found in a French magazine Radio Plans...
Limit alarm (CB9582E)
Using a window comparator, this circuit trips over a certain range of input voltages. Formulas for...
Noise Generator (CB17203E)
This circuit generates a signal rich in harmonics that extends up to close to 1 GHz, serving for...