| 摘要 |
PURPOSE:To avoid temperature dependency for delay time and output pulse width, by using a temperature compensating resistance for an impedance matching resistance of a pulse delay device. CONSTITUTION:An input pulse is inputted to a coil alpha via a wave shaping inverter IC and an input resistance Ri and inputted to an inverter IC via a slide wiper W and outputted with wave shape. The pulse inputted to the coil alpha receives a delay having Td=(L.C)<1/2> of delay time, where L is the inductance of the coil and C is a capacitance between the coil and the ground. A combined resistance value of a termination resistor Ro and a thermister Rth in parallel connection of the circuit at room temperature is set so as to obtain a characteristic impedance Zo=(L/C)<1/2> of the circuit. The resistance Ri is set so that a high- level voltage Vh of a pulse waveform divided with the impedance Zo and the resistance Ri is twice a threshold voltage Vth of the IC, and the ratio of the Ro to the Rth is determined so that the Vh is always twice the Vth in matching with the temperature characteristics of the Vth. Thus, a pulse delay device having stable temperature characteristics can be obtained. |
