1N4148 Signal Diodes

Keith Hilton · Post by **Keith Hilton** » 6 Mar 2000 11:04 pm

I can't find what the forward and reverse breakdown voltage is on the 1N4148 diodes. Can anyone help? Since different types of diodes are used to clamp the inputs of most gear, I wonder what the effect really strong signals has on them. Nowdays a lot of guys have as many as 3 or 4 things creating gain in the signal line. When these very strong signals get to the 1N4148 diodes, I wonder how leakage relates to a noise and hum problem on amps? Seems to me, as these diodes age, the problem would be worse and there would be more leakage. This could be a reason for some of the guy's un-explained hum. I know PEAVEY used to use them a lot to clamp inputs.

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Jack Stoner · Post by **Jack Stoner** » 7 Mar 2000 4:16 am

Keith, I have a Tech America Catalog (Atlanta Ga) (www.techam.com). Here is the spec listing they have for a 1N4148 "Small Signal Detector, Silicon Diodes"
Vrrm Max 100, Io (ma) max 150, Vf max 1.0, @If (ma) 10, Trr (micro sec)4.0, Ct (pf) 4.0

FYI, they list the exact same specs for 1N914, 1N4148 and 1N4448.

Mark Amundson · Post by **Mark Amundson** » 7 Mar 2000 6:47 am

Most 1N4148/1N918 have at least a 100V zener knee (reverse breakdown). Of course forward breakdown is almost unknown as the typical forward bias is between .6 and 1.0 volts and you'll over current the junction long before the forward drop gets larger than a volt (continuous).

Lee Baucum · Post by **Lee Baucum** » 7 Mar 2000 6:42 pm

Are these guys speaking English???

Lee, from South Texas