I just connected a 7.4 volt battery to a 50 ohm resister and connected it to my homemade speaker which is a coil of wire on top of a magnet. I noticed that it drawed current well beyond 148 ma. Why would a coil of wire on a magnet draw so much current?

 

Hello,

Is the 50 Ohms resistor in series or parallel to the "speaker" coil?
Can you post a schematic or a photo of the setup?

Bertus

 

As you can see I used two 100 ohm resistors in parallel to get 50 ohms. The resistors are connected to the speaker in series.

 

Measure the resistance. It must be less than you think.

 

Since I = V / R, since your proclaimed I was higher than expected could be one of three things:
1. "V" is higher than 7.4 V
2. "R" could be lower than the 50 Ohms
3. "I" could have been guessed, measured or read improperly.

I guess it could also be any combination of those three. Double check them all.

 

The problem is that I do not own a multimeter, so checking those things is almost impossible.

 

You can buy a multimeter for less than $10,00 nowadays.

 

You can buy a multimeter for less than $10,00 nowadays.

I thought it was mandatory on this site?
Max.

 

I just noticed I used a comma instead of a period. Oh, well.

 

The problem is that I do not own a multimeter, so checking those things is almost impossible.

What, if any, parts do you have on hand ?

Do you have a DC supply (Wall Wort) voltage regulator IC, op-amp, comparator IC ? etc...

 

I do have a 5v regulator.

 

I just connected a 7.4 volt battery to a 50 ohm resister and connected it to my homemade speaker which is a coil of wire on top of a magnet. I noticed that it drawed current well beyond 148 ma. Why would a coil of wire on a magnet draw so much current?

The problem is that I do not own a multimeter, so checking those things is almost impossible.

I've got a dumb question:

How did you measure the current ???

 

I did not actually measure it. I thought the current was high because I saw sparks.

 

I just noticed I used a comma instead of a period. Oh, well.

You just want to give the impression of being continental!
Max.

 

I saw sparks.

How many?
Max.

 

What color were the sparks ?

Sorry

 

I just connected a 7.4 volt battery to a 50 ohm resister and connected it to my homemade speaker which is a coil of wire on top of a magnet. I noticed that it drawed current well beyond 148 ma. Why would a coil of wire on a magnet draw so much current?

If you dont have a multi-meter, how did you know that the current is well over 148mA?

[edit] sorry! I didn't read page 2....

 

I want to vote this as the thread of the year.

 

What color were the sparks ?

Sorry

When I first started out, the sparks did tell a tale of alloys.

Or, not.

 

Hi Gadersd,

Please don't be offended by a little good-natured ribbing.

It would help if we new what the final goal of this project is.
Do you possibly want to build an amplifier for the speaker, or something else ?