Methods of Discrimination in Power System Protection: Methods of Discrimination in Power System Protection are basically of two types: those which discriminate as to the location of fault, and those…
Important Questions of AC Distribution: 1. How does a.c. distribution differ from d.c. distribution ? 2. What is the importance of load power factors in a.c. distribution ? 3. Describe…
Important Questions of Characteristics of Electric Motors: Problems of Characteristics of Electric Motors: 1.A 50 hp, 220 V, 1200 rpm dc shunt motor has an efficiency of 85% at full…
Thyristors Articles: Silicon Controlled Rectifier Principle Operation: Silicon Controlled Rectifier Principle Operation (SCR) consists of four layers of semiconductor material, alternately p-type and n-type as illustrated in Fig. 19-1(a). Because…
Audio Power Amplifiers Articles: Transformer Coupled Class A Amplifier: Class A Circuit – Instead of capacitor coupling, a Transformer Coupled Class A Amplifier may be used to ac couple amplifier…
Thermistor Operation: The word thermistor is a combination of thermal and resistor. A thermistor is a resistor with definite thermal characteristics. Most thermistors have a negative temperature coefficient (NTC), but…
Optocoupler Circuit Operation: An Optocoupler Circuit Operation (optoelectronic coupler) is essentially a photo-transistor and an LED combined in one package. Figure 20-35(a) and (b) shows the typical circuit and terminal…
Photodarlington Working: The Photodarlington Working shown in (Fig. 20-33) consists of a phototransistor connected in Darlington arrangement with another transistor. This device is capable of producing much higher output currents…