With this circuit we can activate a relay with a simple touch on the sensor. The relay can be 6 or 12 V with current up to 100 mA. The circuit was obtained in my Mechatronics Sourcebook published in the United States. The power supply must in no way be of the transformerless type, as it could cause shocks to anyone who touches the sensor. Equivalent transistors can be used. The circuit has no lock.
