Figure 1-40.-Waveforms.

of the input signal. If the amplitude of the input signal

Under-Over Voltage-Sensing Circuit

is above a specified level, the Schmitt trigger bistable

The under-over voltage-sensing circuit turns the

multivibrator will be in one state (one transistor con-

inverter off when the input dc source voltage is out of

ducting while the other is off); if the amplitude is below

a specified level, it will be in the other state.

the operating range (210 to 355-volts dc) of the inverter.

A modified Schmitt trigger circuit is used to supply

Dc Input Sensing

the interlock signal to the binary circuit in the SYNC

stage. The Schmitt trigger is a form of bistable multi-

The dc input-sensing circuit compensates for

vibrator. It differs from the conventional bistable multi-

changes (step changes) in the input dc voltage source. A

vibrator, in that it is at all times sensitive to the amplitude

Figure 1-40.-Waveforms.

1-34