how to test these components?

[Delphianrex]

hi dear guys,
does any body know how i can test these electronics parts "on circuit or out of circuit?

---8pin Mosfets ( or FET transistors) which are mostly used on laptops?
---Diod
---Crystal Oscillator
---Transformer
---PWM controllers which are used on computer VRM circuits (just with a DMM)


Thanks

 

[(*steve*)]

If you want to test these things with a DMM, then you're not going to be able to test them very much.

In the case of mosfets, you need to look up the datasheets for them, then check for continuity where it's not expected (remembering that neighbouring circuitry can confound your readings)

Diodes are easy (ish). Check for conductivity in one direction and not the other. Beware that dome diodes have a job other than rectification, and also the confounding effects in circuit...

Crystal oscillator -- check the datasheet, the power to the supply pins, then grab an oscilloscope to see if it's generating an output.

Transformer -- ensure you have conductivity through windings and not between them (with the usual caveats about neighbouring circuitry)

PWM controllers -- probably a job for a scope to look at the output.

 

[Delphianrex]

Thanks for your quick reply!
and if i would try test them with with an scope, how could i do that?

is there any good method to test them while they're on the board (using the scope)?
about the crystals, they're the usual crystals which are used with a uc. eg: 11MHz and etc. is there any datasheet for them?