Advertisements
Advertisements
Question
A step-down transformer connected to the main supply of 220 V is used to operate 11V,88W lamp. Calculate
- Voltage transformation ratio and
- Current in the primary
Advertisements
Solution
Given data:
Vp = 220 V, Ps = 88 W, Vs = 11 V
Transformation ratio K = `"V"_"s"/"V"_"p"`
K = `11/220 = 1/20 = 1 : 20 = 1/20`
Current in the primary Ip = ?
`"P"_"S" = "V"_"S" "I"_"S"`
`"I"_"S" = "P"_"S"/"V"_"S" = 88/11` = 8 A
`therefore "I"_"p"/"I"_"S" = "K"`
`"I"_"p" = "KI"_"S"`
`therefore "I"_"p" = 1/20 xx 8 = 2/5 = 0.4`
Ip = 0.4 A
APPEARS IN
RELATED QUESTIONS
Explain the construction and working of the transformer.
State the principle of the step-down transformer and its working.
Find the ratio of primary and secondary currents in terms of turn ratio in an ideal transformer.
How much current is drawn by the primary of a transformer connected to 220 V supply when it delivers power to a 110 V − 550 W refrigerator?
Name the transformer used in the power transmitting station of a power plant.
Complete the following sentence :
……… energy is converted into …………energy by an electric motor.
Given the input current 15 A and the input voltage of 100 V for a step-up transformer having 90% efficiency, find the output power and the voltage in the secondary if the output current is 3 A.
Describe briefly, with the help of labelled diagram, working of a step-up transformer.
A step-up transformer converts a low voltage into high voltage. Does it not violate the principle of conservation of energy? Explain.
State whether true or false. If false, correct the statement.
A transformer can step up direct current.
