Santhakumar Raja

When the field winding of a d.c machine is connected in parallel with the armature, as shown in Fig (a), the machine is said to be shunt wound. If the field winding is connected in series with the armature, as shown in Fig (b), then the machine is said to be series wound. A compound

Power in three-phase loads may be measured by the following methods : One-wattmeter method for a balanced load Wattmeter connections for both star and delta are shown in Fig. Total Power = 3 × wattmeter reading Two-wattmeter method for balanced or unbalanced load A connection diagram for this method is shown in Fig for a

A three-phase supply is generated when three coils are placed 120° apart and the whole rotated in a uniform magnetic field as shown in Fig (a). The result is three independent supplies of equal voltages which are each displaced by 120° from each other as shown in Fig (b). The convention adopted to identify each

There are a number of situations when digital signals have to be converted to analogue ones. For example, a digital computer often needs to produce a graphical display on the screen; this involves using a D/A converter to change the two-level digital output voltage from the computer, into a continuously varying analogue voltage for the

If both inputs of the op amp shown in Fig. 1 are used simultaneously, then from equation, the output voltage is given by: Vo = Ao(V2 − V1) When V2 > V1 then Vo is positive, its maximum value being the positive supply voltage + Vs, which it has when (V2 > V1) ≥ Vs/Ao.

Operational Amplifiers (usually called ‘op amps’) were originally made from discrete components, being designed to solve mathematical equations electronically, by performing operations such as addition and division in analogue computers. Now produced in integrated-circuit (IC) form, op amps have many uses, with one of the most important being as a high-gain d.c. and a.c. voltage