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I have a small board camera to fly first person view on a quadcopter. The camera outputs a PAL/NTSC analog video and is powered off of 12-17 volts (I'm assuming this is regulated)

During a crash, what appears to be a surface mount inductor came off of the board, and the camera doesn't work anymore. The inductor is close to a surface mount SO-23 component marked A7 (a high speed two diode package) and a bunch of discrete resistors/capacitors.

My research turns up surface mount inductors have very, very small values (in the tens of nH). It would be too small for a switching regulator, and there isn't any other reason I can think of for there to be an inductor on an analog camera.

Since the loss of the inductor, the camera does not output anything. Since this inductor is likely of a small value, can I replace it with a short loop of wire? Or is it a serious risk to assume that the exact value of the inductor is unimportant?

Inductor missing from camera

Update: jumping the pins did as expected, the camera turns on but is very prone to interference. Since it's right next to a 5.8g receiver, four brushless motors modulated at 24khz and a bunch of other stuff, it picks up a lot. So that means that it was a ferrite bead. Can I replace this with a loop of wire wrapped around a ferrite ring, or is that long bit of wire still going to pick up garbage?

Update 2: I dismantled a CD-ROM drive and took the ferrite bead. The camera still turns on, but if anything the interference is worse than just with a jumper. I'll try a proper inductor next and see what that does.

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    \$\begingroup\$ What makes you think it's an inductor? My 1st guess would be a cap. \$\endgroup\$ – brhans Nov 18 '16 at 3:19
  • \$\begingroup\$ From my (admittedly limited) experience, a capacitor would either be ceramic (beige color) and/or polarized \$\endgroup\$ – Brydon Gibson Nov 18 '16 at 3:20
  • \$\begingroup\$ Meh - I've seen ceramic caps in all shades of beige, brown, pink, green ... but on further reflection I'm leaning towards AliChen's suggestion of a ferrite bead. \$\endgroup\$ – brhans Nov 18 '16 at 3:36
  • \$\begingroup\$ It can be in series with supply or signal line. So it can be either an inductor or a wire surrounded by a ferrite (this special component is called ferrite bead and its job is suppressing/filtering out the high frequency noise on supply or signal line). If you solder a wire or a 0R 1206 case (IMO) resistor, it can work. \$\endgroup\$ – Rohat Kılıç Nov 18 '16 at 4:28
  • \$\begingroup\$ so where does the regulator reside? \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Nov 18 '16 at 4:39
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This is likely a component called "ferrite bead". It is used for filtering high-frequency noise on power rails. The beads are rated by current carrying capacity, DC impedance, and impedance at 100MHz or something like that. It looks like a 0805 size.It can be replaced by a jumper, but a better way is to get any ferrite bead from Digi-Key, or "borrow" similar bead from some scrap board (old hard drive, CD-rom drive, etc.)

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You cannot tell by looking what a SMD is. It could be an inductor or a resistor or a capacitor or even something else.

Was loss of the mystery component the ONLY casualty of the crash? Do you know for certain that no other parts were damaged?

If the inductor is simply part of a filter circuit, yes, you might get away with shorting across the pads. However, if the inductor is part of a buck regulator circuit (or some other active circuit) then it is possible that you could destroy the board by such an uninformed substitution. Of course, if the board doesn't work anyway, maybe it is worth the risk to you?????

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  • \$\begingroup\$ I have carefully inspected the board and it definitely looks like the only damage from the crash. I'll find a small inductor and try that, since it is less likely to cause damage than just jumping it (IMO) \$\endgroup\$ – Brydon Gibson Nov 18 '16 at 12:43
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enter image description here

  • I would expect it to be 1~10uH 0.1~0.5A for a DC-DC converter 500kHz to 2MHz from the best suppliers such as Taiyo Yuden or TDK

    • The input 12~17Vdc needs to be regulated for video processor probably 5V.
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The interference tells the story - it is a ferrite bead.

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