Diode identification

[shahbaz.ele]

Dear i have a diode written nothing on. Can anyone suggest how to explore its ratings (V & I & P).

 

[mvs sarma]

Dear i have a diode written nothing on. Can anyone suggest how to explore its ratings (V & I & P).

Too generic to answer.
if the item has some metal parts, it is worth the metal value. If a small pastic encapsulated one, better forget it and put in dustbin.

 

[MrAl]

Hi there,

You can explore it's forward voltage drop by running it with a known current
and measuring the voltage across the diode. You can do this for several
currents from 100ua to 10ma and see if the diode gets hot. If not, keep
going. You can then plot a curve.

You also need to check it's reverse characteristics.

You can estimate it's power by noting how hot it gets.

The only way to check it's reverse voltage is to use a voltage supply
(might have to go up to several hundred volts) and check the leakage
current as you increase voltage. Compare with other diodes of known
types and voltage ratings.

In general however it's best to buy a diode so you know for sure
what the characteristics are.

Use that unknown diode for something not too important.

 

[twist2b]

MrAI has it on the spot. To measure something, use a known value in one of these: voltage/resistance/current and then find either of the other 2. After that its all math.

 

[mvs sarma]

Hi there,

You can explore it's forward voltage drop by running it with a known current
and measuring the voltage across the diode. You can do this for several
currents from 100ua to 10ma and see if the diode gets hot. If not, keep
going. You can then plot a curve.

You also need to check it's reverse characteristics.

You can estimate it's power by noting how hot it gets.

The only way to check it's reverse voltage is to use a voltage supply
(might have to go up to several hundred volts) and check the leakage
current as you increase voltage. Compare with other diodes of known
types and voltage ratings.

In general however it's best to buy a diode so you know for sure
what the characteristics are.

Use that unknown diode for something not too important.

We assume that to be able to characterize a diode, a hobbyist would have THIS MUCH power and testing equipment.

Finally I only caution that the device should not blast while in his hands.
Really Is it that important to know all this?
Better keep it in stock or curt the leads and throw if it is a cheap as he got it.

 

[MrAl]

Hi Sarma,

The only thing that i assume is that if he/she has the equipment he/she can
then test the device, and if they dont have the test equipment then he/she
can not test the device. It's also up to them if they feel like getting more
test equipment too if they dont have something they need.

 

[Valence_4]

Where is the diode used ? Power supply rectifier, switching diode, RF detector-mixer, temperature tracker for audio final, polarity protector shunt, VCO varactor, back-to-back clamper, Zener ? Please help us help you !