NTE914
Integrated Circuit
Zero鈥揤oltage Switch
Description:
The NTE914 zero鈥搗oltage switch is a monolithic silicon integrated circuit in a 14鈥揕ead DIP type pack-
age 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:
Limiter鈥揚(yáng)ower Supply: Permits operation directly from an AC line.
Differential ON/OFF Sensing Amplifier: Tests the condition of external sensors or command
signals. Hysteresis or proportional鈥揷ontrol capability may easily be implemented in this section.
Zero鈥揅rossing Detector: Synchronizes the output pulses of the circuit at the time when the
AC cycle is at zero voltage point; thereby eliminating radio鈥揻requency 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 built鈥搃n protection circuit that may be actuated to remove drive from the TRIAC if the sensor
opens or shorts.
Thyristor firing may be inhibited through the acting of an internal diode gate connected to Pin1.
High鈥損ower DC comparator operation is provided by overriding the action of the zero鈥揷rossing
detector. This is accomplished by connecting Pin12 to Pin7. Gate current to the thyristor is
continuous when Pin13 is positive with respect to Pin9.
Features:
D
24V, 120V, 208/230V, 277V at 50Hz, 60Hz, or 400Hz Operation
D
Differential Input
D
Low Balance Input Current: 1碌A(chǔ) Max
D
Built鈥揑n Protection Circuit or Opened or Shorted Sensor
D
Sensor Range: R
X
= 2 to 100k鈩?/div>
D
DC Mode
D
External Trigger
D
External Inhibit
D
DC Supply Voltage: 14V Max
1
2
3
4
