Author Topic: Types of Resistors/Caps  (Read 2043 times)

latchkey

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Types of Resistors/Caps
« on: January 23, 2012, 11:32:47 AM »
Me and a friend of mine are about to embark on some of our first projects from madbean, but we were a little apprehensive when ordering the parts.

1. When looking at the resistors I was unsure when/why I should prefer metal film or carbon film. I understand that they offer different tolerance levels, but I couldn't figure out why different parts of a circuit would need this. Is there any indication on the schematic or something that specifies when a certain tolerance is necessary?

2. When I looked at smallbear I was overwhelmed by the number of different types and brands of capacitors. What types are best for certain values? (for instance I know that electrolytic are best for values larger than 1uF.)

Thank you  ;D

lloyd17

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Re: Types of Resistors/Caps
« Reply #1 on: January 23, 2012, 11:57:12 AM »
Resistors: unless it is specified in the build docs or other folks build reports I don't discriminate between 1% and 5% especially on dirt. I do tend to use 1% where I can but it doesn't bother me to have a few browns mixed among the blues. Don't sweat it.

Caps: general rule of thumb is ceramics for pf values, film for nf values and electros for values greater than 1uf. Beyond that is a preference play really. I used to use greenies but on a tight board they can be too large and unruly so it's pretty much box film caps for me. Just be sure to study the schematic a bit and note which caps are polarized. Those spots get electros.

latchkey

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Re: Types of Resistors/Caps
« Reply #2 on: January 23, 2012, 12:09:26 PM »
Thanks! that was generally what I thought, but it was nice to have someone confirm it.

jkokura

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Re: Types of Resistors/Caps
« Reply #3 on: January 23, 2012, 12:23:33 PM »
1. Only thing I can add to Lloyd's post is that the materials do make a difference, but for what we build it's not noticeable. Metal film leads to a lower noise floor, especially at higher values. So for example, if you built a pedal with Carbon Comp, Carbon Film, and Metal film exclusively, the Metal film would have the least noise, the Carbon Film would be in the middle, and the Comp would be the 'noisiest.' So for that reason, Metal film is considered 'hifi' and carbon comp is considered 'mojo'. Carbon Film is common, cheap and easily a good middle ground. You cannot go wrong using any of those three types.

2. I wish Smallbear had more pictures for their products sometimes. I recommend:
Ceramic for values between 1 and 99pF
Panasonic film for values between 100pF and 920pF
Topmay or Panasonic Film for values between .001mF and .92mF
Topmay or Panasonic Film for Bipolar 1uF
25 or 35V Aluminum Electrolytic caps for polarized 1uf and higher.

Jacob
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