Please assist in identifying this component and its function

StudentSA

Member

• Jul 17, 2012

• #1

Hi,

This is a section of a narrow band FM receiver and I would like to know what the component highlighted in red is?

View attachment 65674

Thanks,
StudentSA

 

Last edited: Jul 17, 2012

Nigel Goodwin

Super Moderator

Most Helpful Member

• Jul 17, 2012

• #2

It's a tuned coil or transformer.

 

KJ6EAD

Active Member

• Jul 17, 2012

• #3

Also known as a slug-tuned variable inductor since it's adjusted by turning the ferrite slug core which is threaded so it moves in or outward with respect to the coil.

 

cowboybob

Well-Known Member

Most Helpful Member

• Jul 19, 2012

• #4

Given the crystal cans around it, it looks like it's part of frequency (perhaps a clock or IF) tuning circuit

 

panic mode

Well-Known Member

• Jul 19, 2012

• #5

tuned coil or transformer, it also may have capacitor in parallel (located underneath) like here:
http://www.electronicecircuits.com/wp-content/uploads/2009/10/IF-Transformer.jpg

capacitor is white cylinder inside the black plastic framework.

these things are used in oscillators and IF stages of receivers. the slot in the top allows them to be tuned to particular frequency.

 

Last edited: Jul 19, 2012

unclejed613

Well-Known Member

Most Helpful Member

• Jul 22, 2012

• #6

a bit of advice... don't try to tune the coil without the proper test equipment, and only use a plastic tool to tune it with. metal tools will break the tuning slug.

 

RCinFLA

Well-Known Member

• Jul 22, 2012

• #7

Likely the 'Quad Coil' for the 455 KHz FM demodulator. It provides the 90 deg phase shift prior to feeding into an EXOR detector to form the FM demodulator.

It will have a small pF cap feeding it. This small value cap may be included on IC die.

https://www.electro-tech-online.com/custompdfs/2012/07/mc3357.pdf