Explorer for all ranges (T1098E)

This circuit was found in a Radio Craft from October 1946. Power supply not shown, and tubes are 1.5V filament types.

EMP Detector (CB23889E)
Originally intended to detect EMPs produced by tests or atomic blasts, this interesting circuit...
Automatic plant sprinkler (CB20778E)
This circuit triggers a small water pump when the humidity detected by the sensor is reduced in a...
Remote power sensor amplifier (CB7444E)
This circuit was found in Maxim's documentation from the 90's. The configuration uses components...