Nonsaturated multivibrators for sensor signal conditioning

Multivibrators based on operational transconductance amplifiers (OTA) are considered. The first is an astable bridge multivibrator with one OTA. This circuit is useful for two-wire bridge-to-frequency converters. The second circuit is an astable multivibrator with two OTAs. This circuit provides a linear dependence of the oscillation frequency on the sensor control current. Both circuits are nonsaturated multivibrators. Calculation of their oscillation frequency involves a linear model which describes the circuit behavior near the transition point from one quasistable state to another. The circuits with bipolar and MOS OTAs are treated.>