Logic operation-oscillation circuit

Abstract

In an 'AND' logic operation-oscillation circuit in which an oscillating output is produced when a signal of a voltage higher than the voltage of a circuit power source is applied a diffused resistor is used for a resistor to which a voltage lower than the circuit power source is applied and a non-diffused resistor is used for a resistor to which a voltage higher than the voltage of the circuit power source is applied, whereby there is constructed a fail-safe circuit in which a short circuit trouble is not caused even if an input signal of a level higher than the voltage of the circuit power source is applied and a phenomenon that an oscillating output is produced even in the absence of an input signal is prevented. In the case where there are laid out a plurality of input signal lines, a conductor maintained at a voltage level lower than the threshold value for initiation of oscillation is arranged between two adjoining non-diffused resistors so that when a short circuit trouble is caused between the non-diffused resistors, an input signal is caused to low in the conductor and the input level is reduced to a low level incapable of producing an oscillating output.