Electronics > Beginners
Does a diode really have a small current flow even when reverse biased
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Adhith:
Hello everyone..
By diodes i meant the general purpose diode 1n4007 and the schottky diode 1n5819. I just reverse biased the 1n4007 with a 12v dc supply(from a wall adapter) and found that even though its reverse biased it has a voltage of 0.7V at the other end. where as the 1n5819 has a voltage of 2.5v at the other end. What does this indicate..are my diodes are bad or does it mean even though it has a voltage flow in reverse bias the current will be very low so that it almost is like an open circuit??
IanB:

--- Quote from: Adhith on July 20, 2018, 08:15:42 am ---I just reverse biased the 1n4007 with a 12v dc supply(from a wall adapter) and found that even though its reverse biased it has a voltage of 0.7V at the other end. where as the 1n5819 has a voltage of 2.5v at the other end.
--- End quote ---

I think you need to elaborate on this statement, because as it stands it does not have any meaning. A voltage is measured between two points. Between which two points are you measuring 0.7 V ? And what does your complete test circuit look like?

In particular, if you apply 12 V DC across a diode in reverse bias, the voltage across the diode will be 12 V. Are you putting a resistor in series with the diode and measuring across the resistor perhaps?

As for your subject question, yes, all diodes have a leakage current. For some diodes, like Schottky diodes, it might be significant.
borghese:
Is not clear; can you post the diagram of your setup?
Raj:
yes,diodes leak some current but I need to see a diagram to know what exactly what you are doing.

Normally,if there is only a diode attached to the source of power,there should be negligable current flow through it and power accross it should be a little less than source (just a few microvolts)

Unless you don't have stable voltage source.In that case,the diode will act somewhat like a capacitor.
leeatljs:
Yes, all diodes have some reverse leakage.
The 1N4007 can 'leak' up to 5uA when reverse biased.  Your 1N4007 is leaking about 700nA into the resistance of your meter.
Schottky diodes leak more when reverse biased.
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