eicpiemann
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Transformer problems

Postby eicpiemann » Sat Mar 18, 2017 1:32 pm

I am building a low power AM transmitter and it showed a 6 pin transformer but the only one I can find is a 5 wire transformer, Help! I cant make my radio work, is this because of the transformer or something else, also there is no p on it to determine what side goes where.

rmarz
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Re: Transformer problems

Postby rmarz » Sun Mar 19, 2017 8:01 pm

eicpiemann - I need a little more information on the design and the transformer. Usually in a simple AM transmitter design, the transformer is an audio output transformer that is used to modulate the power output of the transmitter carrier wave. Typically it is a two winding design, so only 4 connections are available. You may have an audio transformer with a center-tapped primary and a single winding secondary, or a total of 5 connections. If that is the case, you can ignore the center-tap connection and just have a 4 connection, two winding transformer. Any other information on the transformer may be helpful. If you still have difficulties, perhaps you can attach a copy of the schematic and bill-of-materials.

Rick Marz

bfinio
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Re: Transformer problems

Postby bfinio » Mon Mar 20, 2017 8:56 am

Hi eicpiemann - are you following the instructions in this Science Buddies project?

http://www.sciencebuddies.org/science-f ... #materials

If so, is there a reason you weren't able to purchase the suggested transformer from Jameco?

http://www.jameco.com/webapp/wcs/stores ... llDownView

Rick, if he is doing that project, the schematic is on this page: http://www.sciencebuddies.org/science-f ... #procedure

rmarz
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Re: Transformer problems

Postby rmarz » Thu Mar 23, 2017 7:37 pm

eicpiemann - When I looked at the experiment details, they did not provide a schematic diagram. I think that's important and I'm suggesting to Ben that the experiment details be updated to include it. Attached is a typical schematic showing the connections to an audio transformer that has 1000Ω to 8Ω windings. It also shows the 5th connection that you referred to, which I mentioned is the unused 'center tap' for this project. Assuming your transformer is close to these specifications, you should see the transmitter work in the AM band.

Rick Marz
AM-transmitter-update.pdf
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Last edited by rmarz on Fri Mar 24, 2017 2:02 pm, edited 1 time in total.

bfinio
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Re: Transformer problems

Postby bfinio » Fri Mar 24, 2017 5:31 am

Rick - there's a schematic on the background tab of the project, see Fig 2:

http://www.sciencebuddies.org/science-f ... background

[edited this post to avoid future confusion - Rick and I discussed and confirmed that the schematic in Fig 2 of the background is correct]


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