I am in a little trouble and seeking some help. I got a bunch of mixed up diodes from an old collection. I know there are few diodes which are Germanium Diodes. But they look so similar to 1N4148 and similar transparent case diodes. The problem is, the diodes are old (but working) and it's very difficult to read the numbers printed on them. How can I identify and distinguish Germanium diodes? Can I measure something with a multimeter, or create a simple circuit to identify the Germanium diodes. I am looking for identifying diodes like 1N60 and 1N34A. I would highly appreciate your help!
Electronic – How to recognize a Germanium Diode
diodesidentification
Related Solutions
Looks like an 10kΩ NTC. Most NTC's aren't visibly branded, but the resistance at 25 degrees is the property that they are sold by.
Although chances are very slight that it is actually a Vishay part, this page lists a some datasheets for similar devices. Checking the datasheets for a similar part might give you a good feeling for how the device responds to temperature.
Ah... the good old data sheet not showing values or part numbers: -
Yes it is a problem when this happens and sometimes you've just got to figure it out the hard way. It's going to be a fast reverse recovery diode because Cboot is used to generate a dc voltage way above the 15 volt rail and this is being "tickled" at your PWM frequency. I've seen a lot of schottky diodes used here but seriously any fast recovery diode is going to be OK.
Possibly it's an S1 diode from vishay like this but reverse recovery is 1.8us and this strikes me a little long. Probably it's this from NXP - it does say in the data sheet that the marking is S1: -
Typically its reverse recovery time is sub 1us so it's probably OK.
Best Answer
Use this schematic to test the diodes. You can easily distinguish Silicon and Germanium Diodes. Silicon diodes should read approx 0.7V and Germanium diodes should read 0.3V. A little difficult to distinguish Schottky diodes though. They should show approx 0.2V which is close to 0.3V. If you have a very stable power supply and a good meter you can distinguish this as well!
Good Luck!
simulate this circuit – Schematic created using CircuitLab