Touch sensitive electronic switching circuit for electronic wristwatches

Claim 1

A touch sensitive electronic switching circuit for electronic wristwatches including a C-MOS inverter having a P-channel MOS field effect transistor and an N-channel field effect transistor, the gates of the respective transistors being coupled together and the drains of said transistors being coupled together, first and second input terminals for said C-MOS inverter across which an operator's body completes an electrical circuit to initiate switching of said C-MOS inverter from one state to another, a bias voltage source of a first level coupled to the source electrode of said P-channel transistor, a bias voltage source of a second level coupled to the source electrode of said N-channel transistor, said first level being higher than said second level, a pull-down resistor connecting said second input terminal with said bias voltage source of said second level, means connecting said first input terminal to said bias voltage source of said first level, and means connecting said second input terminal to a common gate terminal of the P and N channels of the C-MOS inverter, the improvement comprising: resistor means of a high resistive value connected between said bias voltage source of said first level and the source electrode of said P-channel transistor, the ratio of the resistance of said resistor means to the resistance of said pull-down resistor being within a predetermined range.