Capacitance to Time-Period Conversion Using modified Astable Multivibrator

The work presented is a study of Emitter Coupled Astable Multivibrator. The output time period of this multivibrator is found to be linearly related with the coupling capacitance of the circuit. After the study of the circuit performance, thfe authors suggest that it can be used to obtain a signal conveying the information sensed by capacitive sensors. Also the signal is easy to be ransmitted and measured. The proposed circuit is realizable in IC form, minimizing the problems of shielding and stray capacitance if placed very close to the capacitive transducer.