A charge-flow transistor oscillator circuit

The charge-flow transistor (CFT) turn-on delay time can be monitored with a two-inverter one-latch oscillator. Data are presented for a CFT oscillator incorporating the moisture-sensitive polymer film, poly (p-aminophenylacetylene). An instability of oscillator period is observed in certain bias conditions. The origin of this instability is shown to be charge-averaging the polymer film. The averaging time, which can be extracted from the transient behavior of the oscillator period after power-up, is identified as the bulk dielectric relaxation time of the polymer, and equals 130 s in the present case. A theory of oscillator operation that accounts for the observed behavior is presented, along with a brief illustration of the use of such devices in sensing applications.