Intercom

[flat5]

"I'm glad that we've a veteran electronics expert voice from The Netherlands"

Thank you
Funny you should say that.
I have recently sent a PM asking that "newbie" be removed from my profile. I found it annoying because I've been involved with electronics for over 50 years.
I suggested "sometimes right". I'm not an expert but also not a newbie
Anyway, my request seems to have been honored. I'm honored.
I grew up (5'7'') in California.

 

[Twiggy]

sorry to bump this up again but will 16v 1000uF capactiors work as well as 25v 1000uf capacitors?

 

[Nigel Goodwin]

As long as there's less than 16V across them, they will do just as well.

 

[Twiggy]

great, thanks again.

 

[BrownOut]

The intercom circuit looks like a good one with feedback howling is eliminated by using loud speaker for double purpose. However it is a very old one and the author himself quoted that he already had many years of satisfaction from it

I don't think nowadays anybody go for a fresh assembly using an audio matching transformer which is obsolete.

This Intercom circuit seems to be a good one where the Larsen effect is reduced by a much clever design. Audio quality should be very good and it doesnt require switching over.

I like it! But what the heck is the Larsen effect?

 

[audioguru]

The Larsen Effect is acoustical feedback howling. The full-duplex intercom has a microphone and a speaker. If the microphone can hear the speaker then it will cause acoustcal feedback howling.
The simple intercom uses a "press-to-talk" switch that disconnects the mic at the distant end when you speak while it disconnects your speaker. Then when the other end presses-to-talk it disconnects your mic while it disconnects its speaker when it talks.

The full-duplex circuit electronically cancels the pickup of a speaker by the mic that is near it.

 

[BrownOut]

AH! I always just called that feedback.

 

[Nigel Goodwin]

AH! I always just called that feedback.

Same here!

 

[zipdogso]

I don't know about Brownout (no pun intended.)
But us limeys stick together .... I mean I call it **** not excrement....don't we all ?

 

[transistor495]

I thought somebody will eventually bite on the terminology