1n4148

Hi guys,

We know that the voltage drop across a rectifier diode like 1N4001 is 0.7V in forward bias. What about the voltage drop across a 1N4148? Is a 1N4148 diode in silicon family or it is a germanium diode?

The last question is what If I need to use a high speed diode like 1n4148 but with a current capability of 400mA and a MAX voltage of say 200V? Any diode? Actually I have a switching power supply which originally uses a 1N4148, Now I want to replace the said 1N4148 with a more powerful similar diode, Any suggestion please?

Thanks a bunch

1N4148 is a silicon type, so has a current-dependent forward voltage drop of typically 0.6-0.7V. Google would have told you that.

If I need to use a high speed diode like 1n4148 but with a current capability of 400mA and a MAX voltage of say 200V? Any diode?

Click to expand...

No, not any diode. Go to a supplier's website and check out the diode specs/datasheets.

The 1N4148 is silicon, so .7V. For a high speed diode in a switcher, I would use a Schottky. For instance, a CSD01060A diode has ZERO recovery time, and way higher voltage and current ratings than you need.

In the attached data sheet is a graph of forward voltage verses current.

1N4148 is a fast diode.
1N4001 is a slow diode.

MUR120 1A 200V fast.

The Trr on a MUR120 is ten times slower than the Trr on the 1N4148.

duffy said:

The Trr on a MUR120 is ten times slower than the Trr on the 1N4148.

Click to expand...

Yes!

He is talking switching power supply. The MUR120 is a good diode for that. 45nS.
A 1N4002 is rated at 60hz. Typically does not have a Trr rating because it is so slow. Should never be used in a switcher.

Also try uF4002. Also ten times slower but a good power supply diode.