NTE914

The NTE914 zerovoltage switch is a monolithic silicon integrated circuit in a 14Lead DIP type package designed to control a thyristor in a variety of AC power switching applications for AC input voltages of 24V, 120V, 208/230V, and 277V at 50/60Hz and 400Hz. The NTE914 incorporates 4 functional blocks as follows: LimiterPower Supply: Permits operation directly from an AC line.

Differential ON/OFF Sensing Amplifier NTE914: Tests the condition of external sensors or command signals. Hysteresis or proportionalcontrol capability may easily be implemented in this section.

ZeroCrossing Detector: Synchronizes the output pulses of the circuit at the time when the AC cycle is at zero voltage point; thereby eliminating radiofrequency interference (RFI) when  used with resistive loads.

TRIAC Gating Circuit: Provides high current pulses to the gate of the power controlling thyristor.

The NTE914 also provides the following important auxiliary functions: A builtin protection circuit that may be actuated to remove drive from the TRIAC if the sensor opens or shorts.

Thyristor firing of NTE914 may be inhibited through the acting of an internal diode gate connected to Pin1.

Highpower DC comparator operation of NTE914 is provided by overriding the action of the zerocrossing detector. This is accomplished by connecting Pin12 to Pin7. Gate current to the thyristor is continuous when Pin13 is positive with respect to Pin9.