Please, some one help answer the following silicon diode measurement:

The reading on the test leads to the silicon diode 500 - 800 ohms, when reversing the test leads to the measurement, the reading is 50 - 80 ohms. What is the condition of this diode. Thanks.

 

What readings do you get when you measure a known good diode?

 

If the test is meant to figure out whether the Diode is faulty or not, it seems to me that if this is measurement was done off circuit, then it looks like it is faulty.

 

When positive lead of the Meter
Is connected with Anode of diode
LED glows with negative lead of multimeter

 

the resistance of a siode depends on the meter. older meter types showed different readings than modern digital metrs. the digital meters should show the voltage of the junction when conducting, around .5 to .7 volts for silicon and .2 to .4 for germanium. thats in the foreward direction with the black lead on gthe cathode. reversed it should be nearly open circuit. thats for out of circuit only, in circuit, anything goes, there could be anything across the diode messing up the readings.

 

When positive lead of the Meter
Is connected with Anode of diode
LED glows with negative lead of multimeter

the resistance of a siode depends on the meter. older meter types showed different readings than modern digital metrs. the digital meters should show the voltage of the junction when conducting, around .5 to .7 volts for silicon and .2 to .4 for germanium. thats in the foreward direction with the black lead on gthe cathode. reversed it should be nearly open circuit. thats for out of circuit only, in circuit, anything goes, there could be anything across the diode messing up the readings.

Guys, this thread is four year old!

 

On average, it's actually less than two years old -- and getting younger with every new post! ;-P

 

It curious how new members seem to often engage in raising the dead in these forums.

 

Raising the dead.....it is that time of year.

 

It curious how new members seem to often engage in raising the dead in these forums.

Hi,
Yes that is strange isnt it. And the post that raises the dead often is unrelated to the main topic of the thread. This one was a little related i guess.

 

I have seen on this board that when a person asks a question that has been asked before, he is refered to the origional post. if a person had the decency to search for his question, why not?

 

...Especially that is was never originally satisfactorily answered, as touched on in post #5, you require a meter with a Diode Test range that is capable of passing a current through the diode, the resistance range on modern meters will not do it.
Max.

 

Hello,

A lot of information on diodes can be found on this page of the EDUCYPEDIA:
http://educypedia.karadimov.info/electronics/composemiconductorspassif.htm

There is also a page for the different type of diodes:
http://educypedia.karadimov.info/electronics/composemiconductordiode.htm

Bertus

PS I am closing the thread for old age.
Please start a new thread if you want to know more.