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I'm reverse engineering an old RF transmitter circuit and I can't seem to figure out if the right-most component is a 3 band resistor (+/- 20%) or a capacitor (as the label on the board would indicate).

If it is a resistor, my best guess is that it is 380 ohms. Otherwise, I'm completely at a loss.

Yoshiyahu
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1 Answers1

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It is a Small Disk Capacitor and it's value is 48pF (Yellow, Gray, Black)

More info at: https://www.electronics-tutorials.ws/capacitor/cap_5.html

Nima
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    Highly unusual value and very high too for such a small component. If you read it backwards it’s 47 pF, mush more reasonable. – winny Jan 08 '19 at 09:16
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    It seems you are right @winny. Reading order starts from the thicker band. So I'm going to edit my answer. – Nima Jan 08 '19 at 09:25
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    Changed from downvote to upvote. – winny Jan 08 '19 at 09:26
  • Do small disc capacitors really come in this shape? I can't find any pictures like it elsewhere. It looks like half a resistor, rather than a disk. – Yoshiyahu Jan 08 '19 at 12:33
  • @Yoshiyahu Very uncommon these days. I would not heasitate to swap to a disc if I would repair it. – winny Jan 08 '19 at 13:28
  • I was hoping for more information on this style of component, but this will have to do. I believe that the correct colors (the picture has poor lighting) are orange (not yellow), gray, and brown, making the capacity 380 pF. – Yoshiyahu Jan 08 '19 at 15:38
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    @Yoshiyahu Only you can tell the color accuracy, but 380 pF is still resonable for such a physically small capacitor, although 47 is far more common than 380. 47 is in the E12 series and 380 requires E24. Your board looks one-layer Pertinax which does not ryme well with E24, but not impossible. Measure it with an LCR meter to tell for sure! – winny Jan 09 '19 at 08:42
  • @winny I thought the E value mismatch was also a tad strange, so I found [a picture](https://sep.yimg.com/ay/yhst-16416632405890/raynor-310mhz-flitestar-r-series-garage-door-opener-remote-45.gif) of the same board online. The color on mine must have faded. Yellow, violet, black seems reasonable. Thanks for all your help. – Yoshiyahu Jan 09 '19 at 17:18