Understanding Electrical Concepts Flashcards
Electromotive Force (EMF) is also known as_______.
Voltage
If electricity behaves like water, what is the electrical equivalent of a water valve?
The equivalent is an on/off switch.
The unit of measure of current is _________.
Amps or amperes.
Draw the symbol for an AC (alternating current) supply.
https://www.cleanpng.com/png-electronic-symbol-alternating-current-power-conver-5339765/
If you have a multimeter set to read voltage, and you touch one probe to a circuit part that is energized to 60 volts relative to Earth, and you touch the other probe to a circuit part that is energized to 90 volts relative to Earth, what will the meter read?
30 Volts.
Because it would give you the difference between the reference point set by the first probe and the voltage being measured in the 2nd.
If you touched both probes from a voltmeter to the same point in a circuit, and that point is at 120 volts relative to Earth, what would your meter read?
0 volts.
Because there is no difference between the reference point on the first probe and the voltage being measured on the 2nd probe.
Resistance is the ________ to the free flow of current.
Opposition.
Why is it important to wear gloves when measuring voltage with a voltmeter?
To reduce the risk of shock.
Why is there less risk involved in metering power downstream from the supply?
There is less risk because the conductors are smaller and reduce the amount of energy that can be delivered in the event of a lightning strike, voltage surge, or shock.
Why is it important to measure the voltage before energizing equipment?
It is important to minimize the possibility of applying the wrong voltage to the load.
In the formula:
P = V * I * PF
Which variable is measured in Amps?
The variable ‘I’ (current) is measured in Amps.
The “I” stands for “intensity”
Why would you need a line splitter to measure current?
This is because an amp meter measures the total current inside of the clamp, and if a cable has outgoing and return current the same cable, you will not be able to read the current drawn by the load without using a line splitter to clamp a single conductor.
The ampacity of a cable or wire depends on 5 factors, including: _________, ________, _________, ________, ________.
1.) wire gauge
2.) the temperature rating of the jacket or insulation.
3.) The number of current- carrying conductors in contact with each other
4.) the ambient air temperature
5.) whether or not the conductors are enclosed, or they are in free air.
If you want to leave 20% overhead and a cable with an ampacity of 400 amps, what is the maximum intensity of current that you should allow?
320 amps
The relationship between voltage, current, and resistance is known as ______.
Ohm’s Law
