Trimmers have polarity?

[[email protected]]

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?

 

[John Popelish]

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?

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]

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

 

[Anno Siegel]

Trimmers should be mounted so that the rotor is grounded. It makes
adjustment much easier.

6-30 pF should be OK.

If it isn't, a 60 pF series capacitor brings it to 4.6-20 pF.

Anno