NA556N

IC, PRECISION TIMER DUAL 14-DIP.

The NA556N is a Precision Timer can be operated in the astable and the monostable mode with external resistor-capacitor (RC) timing control. The basic timing provided by the RC time constant can be controlled actively by modulating the bias of the control-voltage input. The threshold and trigger levels normally are 2/3rd and 1/3rd respectively of VCC. This level can be altered by using the control voltage terminal. When the trigger input falls below trigger level the flip-flop is set and the output goes high. If the trigger input is above the trigger level and the threshold input is above the threshold level the flip-flop is reset and the output is low. The reset input can override all other inputs and can be used to initiate a new timing cycle. When RESET goes low the flip-flop is reset and the output goes low. When the output is low, a low-impedance path is provided between the discharge terminal and ground.