Abstract: A self-balancing capacitance bridge-type proximity detector is provided having a probe in one leg of a bridge network and a variable capacitor in the form of a varactor effect tuning diode in the other leg of the bridge network. A high frequency oscillator is coupled to the bridge network and the output of the network from the two legs is equal when the bridge is in a balanced condition. The outputs of the bridge are applied to a differential amplifier for producing an output therefrom on an imbalance of the bridge network which is caused by a metallic object which is to be detected contacting or coming in close proximity with the probe. The output of the differential amplifier is fed back to the varactor tuning diode, changing the capacity thereof to rebalance the bridge network. The output of the differential amplifier is also fed to a shaper circuit and from there to a counter for counting the imbalances of the bridge caused by objects being detected coming into contact or close proximity with the probe.