What kind of component is this?

I removed it from an old broken toy laptop a few weeks ago. I thought it was a capacitor, but when I took a closer look, I was unable to identify it. The lettering says "4.0 MG". 

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AndyGadget7 years ago
It's a resonator.  The 4M shows it's resonant frequency is 4MHz and the G is (I believe) the temperature stability.  It will have been part of the oscillator circuit for the processor.  The way to test to would be to put it in a suitable oscillator circuit, or sweep a  frequency source through it into a spectrum analyser. It should show a sharp drop in the trace at 4MHz.
I agree with Karnuvap - it looks like a resonator to me too.
b-stro (author)  steveastrouk7 years ago
 Would a resonator pass DC current? I just tried it at 1, 3 and 9 volts and didn't pick up anything on my volt meter. I also tried connecting it to a battery, and then connecting the leads (w/ alligator clips), but still didn't detect any voltage. Could it just be a dead component? 
No, it would block DC.
karnuvap7 years ago
I don't think inductance is measured in Gauss. Magnetic field is but inductors are given values of Hernrys.

It could be a ceramic resonator - what was it near on the circuit board? Could it have been adjacent to a micro or parhaps near to the modem (if your laptop had a built-in modem).

To see if it is a conductor you could try a continuity test - a coil would pass DC current whereas a capacitor won't.  (and vice-versa for AC).
b-stro (author)  karnuvap7 years ago
 Unfortunately, I no longer have the circuit board. The board was originally from a children's toy laptop, which was little more than a glorified calculator. It had an LCD screen, a speaker, and a basic keyboard.
lemonie7 years ago
Encapsulated inductor? MG = MilliGauss?