# AC filters.txt

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1. Direct-current combined with alternating current is a common occurrence with electronic circuits this concept is used in many systems as what? NJATC, AC Theory 2nd edition 2009, PP 230 (NC set: AC filters)
As a base voltage and a signal voltage. The AC signals are sometimes referred to as an AC riding on a DC level.
2. AC riding on the DC level is very common in what type of circuits as the DC level is used to operate the amplifier components such as transistors and AC voltage is the signal we want to amplify? NJATC, AC Theory 2nd edition 2009, PP 230 (NC set: AC filters)
amplifier circuits.
3. The low pass filter blocks and passes what frequency range? NJATC, AC Theory 2nd edition 2009, PP 231 (NC set: AC filters)
The low pass filter blocks the high-frequency 100 kHz and passes the low-frequency 1 kHz.
4. What filter classification blocks DC? NJATC, AC Theory 2nd edition 2009, PP 231 (NC set: AC filters)
Transformer coupling, & capacitive coupling.
5. Transformer coupling of amplifier stages is often used in what? NJATC, AC Theory 2nd edition 2009, PP 231 (NC set: AC filters)
Audio amplifiers. These block DC voltage because they are essentially ignored.
6. Capacitive coupling is also known as what? NJATC, AC Theory 2nd edition 2009, PP 232 (NC set: AC filters)
RC filtering.
7. Capacitive coupling or RC filtering is also used when what must be done with the DC and AC voltage? NJATC, AC Theory 2nd edition 2009, PP 232 (NC set: AC filters)
Is used when the DC must be filtered out or blocked, and the AC part of the amplified voltage is allowed to pass.
8. The filter or coupling capacitor is an expensive or inexpensive method to block the DC level? NJATC, AC Theory 2nd edition 2009, PP 232 (NC set: AC filters)
• Inexpensive.
9. The coupling capacitor works why? NJATC, AC Theory 2nd edition 2009, PP 232 (NC set: AC filters)
• Because a capacitor does not allow dc voltage to pass, since it requires a change in voltage in order to discharge.
10. A simple low pass filter uses what in series with a load resistor? NJATC, AC Theory 2nd edition 2009, PP 232 (NC set: AC filters)
An inductor. As frequency increases so does XL, dropping more voltage across the inductor rather than the load.
11. In low pass filter and a high pass filter are designed to pass what at what frequency? NJATC, AC Theory 2nd edition 2009, PP 231 (NC set: AC filters)
Hi pass filters pass high frequencies and low pass filters pass low frequencies.

• The half power point is what? NJATC, AC Theory 2nd edition 2009, PP 234 (NC set: AC filters)
• The point at which the load resistance is dissipating half the max power that could occur at the load.
12. The half power point is typically the point where ______ percent of the source voltage appears at the load. NJATC, AC Theory 2nd edition 2009, PP 234 (NC set: AC filters)
70.7%. 70.7% of the current appears at the load as well. 70.7% voltage x 70.7% current equals 50% of the VA or power, or half PowerPoint.
13. All frequencies to lose less than one half maximum power at the coil are considered to pass to the load. All frequencies the produce more than one half power dissipation at the coil are considered what? NJATC, AC Theory 2nd edition 2009, PP 236 (NC set: AC filters)
Rejected and never reach the load.
14. A capacitive low pass filter does what at low frequencies? NJATC, AC Theory 2nd edition 2009, PP 236 (NC set: AC filters)
• At low frequencies, the capacitor will exhibit a higher reactance, and most of the circuit current will flow through the load resistor rather than the capacitor branch.
 Author: johnbowens ID: 125224 Card Set: AC filters.txt Updated: 2011-12-29 19:28:11 Tags: AC Filters DC NJATC IBEW low pass high filters Folders: Description: Chapter 12 review for NJATC, AC Theory 2nd edition 2009 Show Answers: