Electrical engineering - practice problems - page 9 of 11

Number of problems found: 211

LED circuit calculation
The LED parameters are: ULed is 3 V, Current 100 mA Take measures so that the LED at the U 12 V supply is not destroyed. Perform the calculation and also the wiring diagram.
Resistor current calculation
At a voltage of 16 V between the ends of the resistor, a current of 200 mA flows through the resistor. What current will flow through the resistor when connected to 48 V?
Appliance current calculation
The measurement showed that a current of 160 mA flows through the appliance at a voltage of 4 V. What current flows through this appliance when connected to a voltage of 12 V?
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.
Kilowatt-hours
If the Lewis family used 648 kilowatt-hours of electricity in 12 days at the same usage rate, how many kilowatt-hours should they use in 24 days?
Voltmeter range
We have a voltmeter that, in its original setting, measures up to 10 V. Calculate the resistance of the series resistor (multiplier) needed to extend the range to 50 V. The voltmeter's internal resistance is 2 kΩ/V.
Electric charge time
How long does it take for a 15 C charge to pass through the conductor's cross-section if a 3 mA current passes through the driver?
Orlík hydroelectric plant
The Orlík hydroelectric power plant, built in 1954-1961, consists of four Kaplan turbines. For each of them, the water with a flow rate of Q = 150 m³/s is supplied with a flow rate of h = 70.5 m at full power. a) What is the total installed power of the p
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
Electricity blackout
On Tuesday at 6 o'clock, the electricity supply was interrupted at 156 h. On which day (1 = Monday, ... 7 = Sunday) and at what time was the electricity supply resumed?
Two resistors
Two resistors when they give 25 ohms in series and 4 ohms in parallel, what are 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 = 2200 W, U =?
Bulb 4
In an electric circuit, a bulb (4.5 V, 0.1 A) and a resistor with resistance 45 Ω are connected to a 4.5 V voltage source. Will the bulb shine at full brightness in this circuit? Support your answer with calculations, and possibly look for solutions so th
Electricity consumption
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 ; 40 W Refrigerator; 200 W
Bulbs and electricity
In the sports hall, 875 identical light bulbs are on for 2 hours. How long would 100 such light bulbs need to be on to consume the same amount of electricity?
Light bulb current
There are three light bulbs connected in a row in the circuit. Which light bulb does the largest electric current pass through?
Light Bulb Power Electricity Usage
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?
Resistance
A resistor having an electrical resistance of 1.5 k ohms passes an electrical current of 0.1 A. Calculate the voltage between the terminals of the resistor.
The bulb
Calculate the voltage at the bulb's terminals; if the work 18 J is done to transfer particles with an electric charge of 6 C.

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