Pulse and Digital Circuits

15.2 PULSE SYNCHRONIZATION OF RELAXATION DEVICES

We are going to consider synchronization of the output of a UJT sweep generator using a pulse train. Consider a circuit where a capacitor charges during a finite time interval and the sweep is terminated abruptly by the discharge (relaxation) of the condenser. Such a circuit is called a relaxation circuit. Some relaxation circuits that we have already considered include sweep generators, blocking oscillators and multivibrators. Let us consider a UJT relaxation oscillator shown in Fig. 15.1(a).

Here, the UJT is simply used as a switch. Initially, let the capacitor be uncharged. When the switch is open the capacitor tries to charge to V_BB. The moment the voltage across C reaches V_P(peak voltage or ...