What are these components?

[Mrpong]

Hello, I found some components in my preamplifier. One says "331JF". It's orange and looks like capacitors. The other one says "2A392J. This one is green and also look likes capacitors.

could you please help me encode these components? Thank a lot.

[Vivek]

Any pics possible? That would be useful.

[sbrads]

Originally posted by Mrpong
Hello, I found some components in my preamplifier. One says "331JF". It's orange and looks like capacitors. The other one says "2A392J. This one is green and also look likes capacitors.

could you please help me encode these components? Thank a lot.

The values are probably 330pF for the orange one and 3900pF for the green. That's just based on experience rather than having found them in a catalogue or anything. With codes like these you look for 3 consecutive numbers that make sense in preferred values (e.g. E24 series) and if there's nothing on the capacitor saying what the units are (e.g. pF, uF) then the last digit of the 3 will be the number of zeros with the units being pF, so 105 would be 1uF, 224 would be 0.22uF.

The acid test though is measuring the things but most DVMs don't like small caps in circuit, even the expensive bridge I use at work can get it wrong sometimes and some caps have to lifted to get a true reading.

[Mrpong]

Wow...Thank a lot. Sorry I don't have a digital camera with me now. However, I removed the one with code "2A392J" and measured it. The meter said 4.16nF or 0.00416 uF. I think it should be 3900pF as you said. What does "2A" and "J" mean?

[davidsrsb]

The J suffix usually means 5% tolerance

2A prefix means 100V rating