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.

Humidity Sensor (CB17567E)
This simple humidity sensor can be used in rain or leak detectors. The circuit is for 12 V supply,...
Constant current source LM3900 (CB25176E)
This fixed current source uses a Norton LM3900 amplifier. The maximum current depends on the...
RRRRRTimed alarm for car (CB6776E)
This circuit was found in an EDN from the 90s. The circuit employs a double 555 and uses the...