I have a project where is used a trimmer and it seems that I have isolated the problem to this component.
What I wanted to know is: Trimmers have polarity?
The project must use a trimmer of 5-20 pF but I only could obtain one of 6-30 pF. Do you think that this could cause that the project does not work?
Trimmers should be mounted so that the rotor is grounded. It makes adjustment much easier.
6-30 pF should be OK.Leon
I doubt the value is the problem, unless the original design called for a bigger than needed size. Many trimmers do have non symmetrical form, with one end somewhat shielded from capacitance with the surrounding space by the other end. If the capacitor in your circuit has one end at ground or has a much lower impedance path to ground than the other end, then it may be important that you connect the "outside" end to ground, other wise you will get higher effective capacitance than the trimmer value (the capacitor plus the stray capacitance).
Leon wrote in sci.electronics.design:
If it isn't, a 60 pF series capacitor brings it to 4.6-20 pF.
Anno
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