# ceramics capacitors?

Discussion in 'General Electronics Chat' started by Mathematics!, Feb 22, 2009.

1. ### Mathematics! Thread Starter Senior Member

Jul 21, 2008
1,022
4
ceramics capacitors what is the capacitance?

I have radio shack part 272-801 pkg. of 100

But the only thing on each capacitor is an underlined number.
Like

151
----

1
--

...etc are these in uF, nF, pF , F or what?

And with these ceramic disc capacitors does it matter which way I put them in?

Their legs are both the same size. So I don't think their is a difference no plus sign or - on any sides.

May 16, 2005
5,072
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3. ### AlexR Well-Known Member

Jan 16, 2008
735
54
The marking 151 means that is a 150pF capacitor.
Under this numbering scheme the first 2 digits are the value and last digit is the number of zeros to add to the end of value. It is always expressed in picofarad.

4. ### Mathematics! Thread Starter Senior Member

Jul 21, 2008
1,022
4
What happens if I have just
1 is that 1pF because not all of these capacitors have 3 digit numbers.
-

What happens for the 1 or 2 digit numbers ? Do I take the missing digits to be zero's?
And will their every be a 4 or 5 digit number ...?

Also I am just wondering in electronics what the most used sizes for a capacitor is.
Is it like pF or nF or uF ??? And the usually range. I know they all have uses but just wondering what the majority of them and their ranges.

Last edited: Feb 22, 2009

Apr 5, 2008
15,806
2,389
6. ### SgtWookie Expert

Jul 17, 2007
22,183
1,728
Yes.

No. For the capacitors that you purchased, a 1 or 2 digit value is the capacitance in pF.

Not in that assortment.

It depends upon the application. For a DC power supply, you might use a 10,000uF capacitor after the bridge rectifier, and a 10uF plus a 0.1uF cap after the regulator. If you're building a TTL or CMOS logic circuit, you'll use 0.1uF (100nF) "bypass" capacitors across the supply pins to help keep transients under control.

Low pF values are used in radio frequency circuits.
High pF/low nF values can be used in timer/oscillator circuits.
100nF caps are widely used as bypass capacitors, also used in timer/oscillator circuits.
1uF-100uF caps are frequently used in audio applications.
Larger caps are usually used in power supplies.