# Help on Resonant Circuits

Discussion in 'Homework Help' started by Corey Esson, Feb 8, 2015.

1. ### Corey Esson Thread Starter Member

Feb 8, 2015
30
1
Hi all, new here and like the whole site.
I'm having issues with some online electronics classes/homework.
The quest I can't find in my lesson is: All receivers, regardless of what type, have at least one:
A. Power supply
B. Tuning fork
C. Vacuum tube
D. Resonant circuit

I have it narrowed down to either A or D but not quite sure. Thanks in advance for any all all help.
Corey

2. ### crutschow Expert

Mar 14, 2008
16,569
4,475
So which of those two are absolutely required for operation even if you know nothing else about he design of the receiver circuit.

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3. ### Corey Esson Thread Starter Member

Feb 8, 2015
30
1
I found it finally! Its "D". Resonant circuit

4. ### Corey Esson Thread Starter Member

Feb 8, 2015
30
1
I know now that the resonant circuit is but thought the power supply was but found it wasn't. Thank you very much!
Corey

5. ### crutschow Expert

Mar 14, 2008
16,569
4,475
How can a receiver work without power?

And certainly you can make a receiver without a resonant circuit (although perhaps not easily) using all digital processing.

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6. ### Corey Esson Thread Starter Member

Feb 8, 2015
30
1
Very true when you put it that way for sure. Thank you.
Corey

7. ### WBahn Moderator

Mar 31, 2012
20,256
5,759

The power comes from the signal itself, and not a power "supply".

But I agree that a receiver doesn't absolutely have to have a resonant circuit, either.

So I think the answer depends on what the person writing it had in mind as far as the "fine print".

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8. ### JoeJester AAC Fanatic!

Apr 26, 2005
3,676
1,537
With a topic titled Resonant Circuits, the answer was sort of a gimme. The problem is the distractors should sound feasible, but not correct.

Answer A is also correct, unless your going to discriminate between power supplies and batteries ... calling them a power source. Multiple Choice (guess) questions need good distractors to have some level of validity and a decent degree of difficulty.

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9. ### WBahn Moderator

Mar 31, 2012
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5,759
Don't forget about the good ole fashioned crystal radio! No power supply. No battery. Just a long wire, an inductor (wire wound on a toilet paper tube), a capacitor (I used a two liter soda bottle with aluminum foil taped on each side), a germanium diode, and a high-impedance earphone.

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10. ### JoeJester AAC Fanatic!

Apr 26, 2005
3,676
1,537
Very true WBahn. The crystal is a resonant circuit.

Even antenna can be a bad distractor.