Circuit Problem

JoeJester

Joined Apr 26, 2005
4,259
Do you have the test equipment to make some tests?

Have you measured anything? If so post what you measured ... and where you measured it.
 

brockrwood

Joined Oct 23, 2016
47
Please help me!!!

I have built the intercom circuit found at (
http://www.uoguelph.ca/~antoon/circ/intercom.html ), but it does not
work.

Are the audio transformers necessary with the 8ohm speakers? I cannot get any noise on the line at all. No sounds comes out from anywhere.

Any ideas?

Thanks
-Chad
You definitely need the transformers if you want to use 8 ohm speakers. One transformer for each speaker. The 8 ohms impedance is too low for the amplifier circuit. You need a transformer that presents a higher impedance to the amplifier (primary) with a lower impedance on the secondary, facing the speaker. Do a google search for "8 ohms audio transformer".
 

brockrwood

Joined Oct 23, 2016
47
You're trying to answer a post that was 10 years old when you joined. Necroposting to a 12 year old thread must be a record.
I see your point. In my defense, however, other people viewing the thread may have a similar problem right now, at the current time. MY reply to the original post was intended to help any people on AAC who view the thread and have a similar problem.
 

sghioto

Joined Dec 31, 2017
1,038
brockrwood I'm just curious how you found that post. I believe it was on page 1569 of 1575.
Did you start from the last page and start working backwards?:)
SG
 

brockrwood

Joined Oct 23, 2016
47
brockrwood I'm just curious how you found that post. I believe it was on page 1569 of 1575.
Did you start from the last page and start working backwards?:)
SG
You guys are being unnecessarily mean to me. I stand by my convictions! I do right by the members of AAC! I help, even if the problem is 13 years old! ;-) Maybe he hasn't figured it out yet and the circuit, on a breadboard, is still floating around at the bottom of his "circuit projects in progress" box? I have such a box. There are half-built circuits in there from 5 or 6 years ago. Oops. Maybe I should not admit that... ;-)

How I found the post: I was doing my OWN search on the right values to use for an audio output transformer for a similar circuit. Badda-boom, badda-bing, this old post popped up.
 

brockrwood

Joined Oct 23, 2016
47
They are only mean to people they like...

...and people they don't like.

But I am pretty sure they like you.
Yes, I know. That was the reason for my winky faces. ;-). And I appreciate the experts on AAC putting up with my sometimes uninformed hobbyist level questions. The willingness of the AAC members to give so freely of their time and expertise is awesome!
 

MrAl

Joined Jun 17, 2014
7,473
I see your point. In my defense, however, other people viewing the thread may have a similar problem right now, at the current time. MY reply to the original post was intended to help any people on AAC who view the thread and have a similar problem.
Hi,

What is amazing to me is that we actually see threads this old. It doesnt seem that long ago but wow it was. Let's see, 2019 minus 2006, that's something like 12 to 13 years old. However, most information dies very slowly over decades and this thread is still relevant.
It's hard to believe that i posted some in other forums around 1998. That's more than 20 years ago! Geeze.
 

nsaspook

Joined Aug 27, 2009
7,181
Hi,

What is amazing to me is that we actually see threads this old. It doesnt seem that long ago but wow it was. Let's see, 2019 minus 2006, that's something like 12 to 13 years old. However, most information dies very slowly over decades and this thread is still relevant.
It's hard to believe that i posted some in other forums around 1998. That's more than 20 years ago! Geeze.
Time passes on. In the 80's I was running a dial-up technical forum BBS on a Convergent Technologies "Miniframe" (later a MegaFrame) from my house. The questions were pretty much the same at the basic circuit level.
 
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