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)...
Category - Electrical
There are broadly two sources of losses in transformers on load, these being copper losses and iron losses. Copper losses are variable and result in a heating of the conductors, due to the fact that they possess resistance. If R1...
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...
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...
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...
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...
Operational Amplifiers (usually called ‘op amps’) were originally made from discrete components, being designed to solve mathematical equations electronically, by performing operations such as addition and division in...
Networks in which electrical energy is fed in at one pair of terminals and taken out at a second pair of terminals are called two port networks. The network between the input port and the output port is a transmission network for...
The maximum power transfer theorem states: The power transferred from a supply source to a load is at its maximum when the resistance of the load is equal to the internal resistance of the source. Hence, in Fig when R = r the...
Table summarises the characteristics of some typical bipolar junction transistors for different applications, where IC max is the maximum collector current, VCE max is the maximum collector – mitter voltage, PTOT max is...
