Will this diode heat up?

I want to put this diode, http://www.digikey.ca/product-detail/en/SB560-E3/54/SB560-E3/54GITR-ND/1023528 , in line and cover it with heat shrink tubing. It is rated for 60 volts and 5 amps, significant overkill for my purpose but I happen to have one here.

Its primary purpose is to disallow current to flow, no current would be flowing through it in normal use, however in an emergency situation (eg: I would be about to make an off airport landing) there would be a very small current ~ 40 mA at 12 volts drawn through it.

Question 1: Does a diode heat up significantly when it is only being used to stop current flow?

Question 2: Would such a small current cause it to heat significantly?

SMO said:

Question 2: Would such a small current cause it to heat significantly?

Click to expand...

In general, no

The heat dissipation in watts will be the diode drop x the current. In your case, that would be approx 0.3V x 40mA = 12mW. The forward voltage came from the data sheet forward characteristic curve at 40 mA.

SMO said:

Question 1: Does a diode heat up significantly when it is only being used to stop current flow?

Click to expand...

In general, no

If you look at the reverse characteristics, they are very dependent on temperature. At room temp and 12V you are looking at 0.001mA leakage. At 75deg C, closer to 0.1mA. 0.1mA x 12V is 1.2mW, nothing to worry about.

Paige

1. No, it would not get even slightly warm when blocking current flow.
2. No, 40ma would not cause this diode to heat significantly.

According to ohm's law, power (heat) = current squared x resistance. So smaller current results in less heat. You would not be able to detect a temperature difference with your fingers when the diode is conducting 40ma.

THANKS FOLKS!