A control circuit with a high voltage sense device. A flow path extends through the instrument body to the watertight space and this flow path is closed by a membrane, which is permeable by a gas, but not by water, and which closes the flow path in a watertight manner. Combination means for combining said error signal with said amplified signals to produce said compensated output signal; and control means for controlling said phase shift means in dependence on the relative phase difference between the control signal in said input signals and the control signal in said amplified signals. Applying a limited current to a sourcedrain region during an erase operation can cause the sourcedrain region and a floating gate to rise together and avoid band-to-band tunneling and resulting hole injection into the floating gate.