Save
Upgrade to remove ads
Busy. Please wait.
Log in with Clever
or
show password
Forgot Password?
Don't have an account?  Sign up 
Sign up using Clever
or
Username is available taken
show password


Make sure to remember your password. If you forget it there is no way for StudyStack to send you a reset link. You would need to create a new account. Your email address is only used to allow you to reset your password. See our Privacy Policy and Terms of Service.

Already a StudyStack user? Log In

Reset Password
Enter the associated with your account, and we'll email you a link to reset your password.
focusNode
Didn't know it?
click below
 
Knew it?
click below
Don't Know
Remaining cards (0)
Know
0:00
edit
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

  Normal Size     Small Size show me how

AC Theory

Lesson 5

QuestionAnswer
Only ____ opposes current flow in a DC circuit. resistance
Is resistance the only thing that opposes current flow in an AC circuit? no
Give your opinion on whether the inductive and capacitive elements in a circuit may be ignored when making resistive circuit calculations for field installations. No. You can't ignore them. They will be used to help you with your calculations.
____ produces heat when current passes through. resistance
The average value of a pure sine wave is ____. 0
How can instantaneous current values be determined? I inst= I peak x sin(Θ)
What is the instantaneous value of a 10 amperes peak sine wave at 30°, 45°, and 60°? I inst = 10 x sin (30°) = 5A I inst = 10 x sin (45°) = 7.07A I inst = 10 x sin (60°) = 8.66A
What is the instantaneous value at 0° and 180°? 0
Current and voltage in an AC resistive circuit and ____ (in/out of) phase. in
Besides a sine wave is there another method to depict the relationship of voltage and current in phase? vectors
Can voltage and current be added together? No. You can not add voltage and current together. Vector additions of electrical circuits can only be preformed with like values.
A voltage of 600V peak-to-peak is connected to a 20 ohm heater. What is the wattage? E peak = 600/2= 300V E rms = 300/1.414= 212V P = 212²/20 = 44944/20 = 2247.2 W
Prove that the question below is true. E peak = 300 V 20-ohm heater. P= E peak x I peak/2 I= 300/20= 15A P= 300 x 15/2= 2250W
Does a particular conductor offer the same opposition to current flow in an AC circuit as a DC circuit? No. In a AC circuit you can have skin effect which will increase resistance.
What two factors, not present in a DC circuit, affect the opposition to current flow in an AC circuit? skin effect and induction of eddy currents
Which of these effects can be reduced using stranded conductors? (skin effect & induction of eddy currents) Why? Skin effect. Stranded provides more surface area than a solid conductor of an equal size, also helps reduce the overall negative effect.
What effect would a frequency higher than 60 Hz have on "skin effect"? As the frequency increases, the magnitude of the eddy currents increases. Causing the skin affect to increase
The effective value of AC voltage will produce the same amount of ____ as a like value of ____ voltage. power DC
When an AC voltage is given, it is always the ____ value unless stated otherwise. effective
A pure AC sine wave has an average of ____ volts because the amount above zero is ____ as much as the amount below zero. 0 exactly
The average value is the actual average of the ____ voltage or current values across a full cycle. instantaneous
The average value of halfwave rectified DC is ____ times the peak AC value or one half of the ____ value 0.381 full wave rectified
Created by: SM76502
 

 



Voices

Use these flashcards to help memorize information. Look at the large card and try to recall what is on the other side. Then click the card to flip it. If you knew the answer, click the green Know box. Otherwise, click the red Don't know box.

When you've placed seven or more cards in the Don't know box, click "retry" to try those cards again.

If you've accidentally put the card in the wrong box, just click on the card to take it out of the box.

You can also use your keyboard to move the cards as follows:

If you are logged in to your account, this website will remember which cards you know and don't know so that they are in the same box the next time you log in.

When you need a break, try one of the other activities listed below the flashcards like Matching, Snowman, or Hungry Bug. Although it may feel like you're playing a game, your brain is still making more connections with the information to help you out.

To see how well you know the information, try the Quiz or Test activity.

Pass complete!
"Know" box contains:
Time elapsed:
Retries:
restart all cards