Advertisements
Advertisements
प्रश्न
Answer the following question.
Draw the diagram of a device that is used to decrease high ac voltage into a low ac voltage and state its working principle. Write four sources of energy loss in this device.
Advertisements
उत्तर
A transformer is a device that is used to either increase or decrease the ac voltage level. In order to decrease the high ac voltage level into a low ac voltage level we need a step-down transformer, whose diagram is as follows:
Working Principle:
A transformer works on the principle of electromagnetic induction. Alternating current in the primary coil produces a changing magnetic flux due to this an induced current is set up in the secondary coil. Losses in a transformer: Copper loss - The windings of the transformer have finite resistance due to which some energy is lost in the form of heat. It can be diminished using thick copper wires.
Iron loss - Loss is in the bulk of iron core due to the induced eddy currents in the iron core. It is minimized by using a thin laminated core.
Hysteresis loss - Alternating magnetizing and demagnetizing of the iron core causes the loss of energy in the form of heat. It is minimized using a special alloy of the iron core with silicon that has low hysteresis loss.
Magnetic loss - All the magnetic flux due to the primary coil does not pass through the secondary coil. So there is some leakage of flux. This loss can be minimized by winding primary over the secondary coil.
संबंधित प्रश्न
The potential difference across the resistor is 160V and that across the inductor is 120V. Find the effective value of the applied voltage. If the effective current in the circuit be 1.0 A, calculate the total impedance of the circuit.
In series LCR circuit, the phase angle between supply voltage and current is ______.
Which of the following components of an LCR circuit, with a.c. supply, dissipates energy?
A series LCR circuit containing a 5.0 H inductor, 80 µF capacitors, and 40 Ω resistor is connected to a 230 V variable frequency ac source. The angular frequencies of the source at which power is transferred to the circuit are half the power at the resonant angular frequency are likely to be ______.
Define Impedance.
An alternating voltage of 220 V is applied across a device X. A current of 0.22 A flows in the circuit and it lags behind the applied voltage in phase by π/2 radian. When the same voltage is applied across another device Y, the current in the circuit remains the same and it is in phase with the applied voltage.
- Name the devices X and Y and,
- Calculate the current flowing in the circuit when the same voltage is applied across the series combination of X and Y.
Select the most appropriate option with regard to resonance in a series LCR circuit.
Which of the following combinations should be selected for better tuning of an L-C-R circuit used for communication?
A resistance of 200Ω and an inductor of \[\frac {1}{2π}\]Н are connected in series to a.c. voltage of 40 V and 100 Hz frequency. The phase angle between the voltage and current is ______.
To an ac power supply of 220 V at 50 Hz, a resistor of 20 Ω, a capacitor of reactance 25 Ω and an inductor of reactance 45 Ω are connected in series. The corresponding current in the circuit and the phase angle between the current and the voltage is respectively:
