Electrical engineering - high school - practice problems - page 3 of 4
Number of problems found: 72
- Coils of transformer
The primary coil of the transformer has 400 turns. A current of 1.5 A passes through it and is connected to a voltage of 220 V. For the secondary coil, find the voltage, current, and a number of turns if the transformation ratio k = 0.1. - Transformer
Transformer - U1 = 230 V, N1 = 300, N2 = 1,200, I1 = 4 A. Calculate the transformation ratio, voltage and current in the secondary coil. - Respective 25361
Three resistors are connected according to the scheme (R1 in parallel with R2 and series with R3: R1||R2 + R3) so that R1=0.6 Ω, R2=2 Ω, R3=3 Ω, current I1 = 10 A. Calculate all the currents passing through the respective resistors R1, R2, R3 and all the - Resistances 25281
Three resistors with resistances of 200 Ω, 400 Ω, and 600 Ω are connected next to each other (parallel). A current of 1.8 A flows through the first 200Ω resistor. a) What current passes through the second and what current through the third resistor? b) Wh
- Lowest voltage
Three resistors with resistors R1 = 10 kΩ, R2 = 20 kΩ, R3 = 30 kΩ are connected in series and an external voltage U = 30 V is connected to them. On which resistor is the lowest voltage? - Closed circuit
There is a voltage source with U1 = 12 V in a closed circuit and with internal resistance, R1 = 0.2 Ω. The external resistance is R2 = 19.8 Ω. Find the electric current and terminal voltage. - Short-circuit 22841
An external circuit with a resistance of 3.8 Ω is connected to an electrical voltage source with Ue=12 V. A current of 3 A passes through the circuit. Specify: source terminal voltage, the internal resistance of the source, maximum short-circuit current. - Energy consumption
The device is connected to 230V and draws a 3.5A current. Power consumption is 1932kJ. How many minutes has this device been in operation? - Transformer 20073
The transformer is oil-cooled and transforms a power of 20MW with an efficiency of 92%. Determine the temperature of the oil at the outlet of the transformer if the oil was 20°C when it entered the transformer. 2.5 liters of oil will flow through the tran
- Calculation 16653
The LED parameters are: ULed is 3V, Current 100mA Take measures so that the LED at the U 12V supply is not destroyed. Perform the calculation and also the wiring diagram. - 3 phase load
Two wattmeters are connected to measure power in a 3 phase balanced load. Determine the total power and power factor if the two wattmeters read 1000 watts each (1) both positive and (2) the second reading is negative. - Voltmeter range
We have a voltmeter which, in the original set, measures voltage to 10V. Calculate the size of the ballast resistor for this voltmeter if we want to measure the voltage up to 50V. Voltmeter's internal resistance is 2 kiloohm/Volt. - Effective and mean voltage
A voltage divider consisting of resistors R1 = 103000 Ω and R2 = 197000 Ω is connected to the ideal sine wave voltage source, R2 is connected to a voltmeter which measures the mean voltage and has an internal resistance R3 = 200300 Ω, the measured value i - Two resistors
Two resistors when they give 25 ohms in series and 4 ohms in parallel, what the values of
- Transformer
Solve the textbook problems - transformer: a) N1 = 40, N2 = 80, U2 = 80 V, U1 =? b) N1 = 400, U1 = 200 V, U2 = 50 V, N2 =? - Electric input power
Solve problems related to electric power: a) U = 120 V, I = 0.5 A, P =? b) P = 200 W, U = 230 V, I =? c) I = 5 A, P = 2200W, U =? - Refrigerator 6703
Calculate how much we will pay for 1 hour of consumed electrical energy if the seller sets a price of 0.126 euros for 1 kWh (all appliances together for 1 hour of work). Table: Appliance Power (W) Washing machine 2300 W Bulb 40W Refrigerator 200W TV 110W - Connected 6668
There are three light bulbs connected in a row in the circuit. Which light bulb does the largest electric current pass through? - Electricity 6667
A light bulb with power consumption P = 70 W. It is connected to a mains voltage of 230 V. How big is the electric current that flows through it? How much electricity in kWh will it use if it is on for 9 hours 30 minutes?
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