Anyone know what this is?

[GandJ]

Found this inline before our 20 year old car radio. Is it some kind of suppressor or capacitor (resembles a mini transformer!?) -- struggling to find a new fuse where we are in France?

 

[Cymrogwyllt]

It may well be there to kill interference from the ignition system.

 

[sailorman]

looks like a transformer to me

 

[Elemental]

It's not a transformer - that would normally require more wires. I'm sure it's a noise suppression coil. It may not be required - try it and see. Its absence may be more noted if listening to AM (LW/MW) rather than FM.

 

[SAMYL]

It's a choke to smooth out fluctuations in the power supply which cause 'hum'.

 

[nigelmercier]

It's a choke to smooth out fluctuations in the power supply which cause 'hum'.

It is indeed a choke, but it is to remove high frequencies, not hum.

 

[JumbleDuck]

Flux capacitor.

 

[lw395]

It is indeed a choke, but it is to remove high frequencies, not hum.

+1.

 

[GandJ]

Many thanks for all your prompt replies. I shall endeavour to source a replacement fuse when location allows -- in the meantime I can experiment without it, fusing the wire separately.

 

[macnorton]

It is indeed a choke, but it is to remove high frequencies, not hum.

+2
mainly used to reduce noise created by the points in a petrol engine ignition or alternator whine, with a diesel engine and modern alternator you don't need it and the radio will work fine without it.

 

[SAMYL]

It is indeed a choke, but it is to remove high frequencies, not hum.

Ah well, same idea anyway.

They are used to smooth out oscillations in a DC power supply from a dynamo or other rectified power source which can cause hum.