Author Topic: Trimmer Capacitors  (Read 951 times)

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Offline Polybus

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Trimmer Capacitors
« on: May 30, 2015, 03:49:14 pm »
Following on from the success (??!?!?) of my recent AM Transmitter - I'm going to have a go at an FM one.

I need a couple of 6pF to 40pF Variable Capacitors.

Now here is the real newby question.

Are these things Variable Capacitors??

http://www.ebay.com.au/itm/50-x-40pF-6mm-2-Pin-Ceramic-Trimmer-Capacitor-Replacement-Yellow-/331551678628?pt=LH_DefaultDomain_15&hash=item4d320520a4

They call them Trimmer capacitors - which I guess is just another name for Variable Capacitors, but in the specs they only nominate them as 40pF. I've seen very similar components that are adjusted with a little screwdriver.

Specification:
Product Name   Trimmer Capacitor
Capacitance   40pF
Mounting Type   DIP Through Hole
Diameter   6 mm / 0.24"
Pin Spacing   5 mm / 0.2"
Total Length   8 mm / 0.3"
Material   Ceramic, Metal
Weight   16g
Main Color   Yellow
Package Content   50 x Trimmer Capacitors


Should I just take it as assumed that they are 0pF to 40pF?? And they just leave the 0pF out of the specs because its just assumed?? Or am I missing something here?

Thanks heaps.

Polybus
« Last Edit: May 30, 2015, 03:50:49 pm by Polybus »
 

Offline ivaylo

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Re: Trimmer Capacitors
« Reply #1 on: May 30, 2015, 04:18:01 pm »
Yes, they are variable capacitors. You can ask the seller what the range is. Here is a similar listing where it is spcified http://www.ebay.co.uk/itm/Ceramic-Trimmer-Variable-Capacitor-Green-5-2-40pF-2Pk-/121545592980 Tolerance isn't great on these things though, so expect variation from they say the range is...
 

Offline Polybus

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Re: Trimmer Capacitors
« Reply #2 on: May 30, 2015, 05:06:46 pm »
OK thanks.

From that answer I take it that I can't assume they start from 0pF.

I'll write to the vendor and see what they say.

Cheers.
 

Offline SeanB

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Re: Trimmer Capacitors
« Reply #3 on: May 30, 2015, 05:23:53 pm »
40pF max, and probably minimum is 10pF or so. The low value ones are pretty poor, and you will find that they are fiddly to adjust, you need the right non metallic ceramic tool to do it.
 


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