This integrated amplifier was used in televisions from the 70s, with good sensitivity characteristics. The circuit was powered with 9 V.
In the figure we have a more elaborate application of a timer that activates two relays in a...
This circuit triggers a small water pump when the humidity detected by the sensor is reduced in a...
This circuit makes use of the Linear Technology LT6100. We find it in a 2005 company manual. The...