Recovered diode identification request

[fuzz]

I pulled a pile Of these diodes from a Hewlett Packard pulse generator. Unknown era, but my guess is 1960’s.

There looks to be a Fairchild “F” on the base but I cannot confirm. Vf according to my Peak is .595 to .659 @ 5.00 mA. They are black glass, brown stripe at cathode end and a yellow in the middle. Blue F at anode end.

Mostly curious about applications, usually diodes of this size/material are germanium but the Vf, as well as not knowing if silicon diodes were made in this type of size/housing has me questioning this.

 

[darwin999]

I would suggest that you do an internet search for the service manual for that HP pulse generator, and then look them up

 

[PedalBuilder]

I pulled a pile Of these diodes from a Hewlett Packard pulse generator. Unknown era, but my guess is 1960’s.

There looks to be a Fairchild “F” on the base but I cannot confirm. Vf according to my Peak is .595 to .659 @ 5.00 mA. They are black glass, brown stripe at cathode end and a yellow in the middle. Blue F at anode end.

Mostly curious about applications, usually diodes of this size/material are germanium but the Vf, as well as not knowing if silicon diodes were made in this type of size/housing has me questioning this.

Does the Vf change if you hold the diode between your fingers? If it changes, then it’s germanium. If it’s the same, then it’s silicon.

 

[fuzz]

I would suggest that you do an internet search for the service manual for that HP pulse generator, and then look them up

Excellent! I’m embarrassed to admit but this idea never even occurred to me. Found the schematics and service manual, all it says is silicon diode but it confirms things. Super helpful idea, I have a pile of other electro with questionable components, looks like I have some detective work ahead of me!