Help identifying components

[DaveC]

Black diode, smaller than 1Nxxx, green band and green test: "R47".

Glass diode with yellow band. No other markings.

Thanks.

 

[Josepi]

May be house component marked and only identifiable ny the circuit board
design people.

Check for forward voltage drop for Ge or Si, then Zener PIV and most of the
rest doesn't matter.

Second unit is probably a Ge diode like 1N34A



Black diode, smaller than 1Nxxx, green band and green test: "R47".

Glass diode with yellow band. No other markings.

Thanks.

 

[DaveC]

Black diode, smaller than 1Nxxx, green band and green test: "R47".

should say 'green text: "R47" '.

Thanks.

 

[DaveC]

Check for forward voltage drop for Ge or Si, then Zener PIV and most of the

rest doesn't matter.

0.58 v-drop.

How to check for Zener PIV?

Thanks.

 

[DaveC]

What are they in? A little context would help.

The circuit is in a Hakko 472 desolder station. It controls the switching on
and off of the vacuum pump motor and vacuum solenoid valve.

Thanks.

 

[Tim Williams]

DIAC?

I have some diodes of similar appearance on RF equipment. I'm guessing
they are either schottky or varactor. YMMV, could be a manufacturer
thing.

Tim

 

[DaveC]

Second unit is probably a Ge diode like 1N34A

Measures 0.59v drop. So: silicon.

 

[DaveC]

Does the fact that both show ~ 0.6 v-drop rule out zeners?

Thanks.

 

[DaveC]

Are the vacuum pump and solenoid AC or DC devices?

AC

Is there a SCR in there?

2 triacs: one for the motor, one for the solenoid.

See if this schematic has any think close to what you have:

http://www.eserviceinfo.com/downloadsm/37779/Hakko_850B.html

Not much similarity. The 850 uses a 120vac motor; the 472 uses a 35 vac
motor. The 850 has no solenoid.

Thanks.

 

[Rich Grise]

0.58 v-drop.

How to check for Zener PIV?

Variable DC supply, 1 meg resistor, series circuit with diode reverse-
biased. Watch the diode voltage as you increase the supply voltage.
When it levels off, you've reached reverse breakdown.

Hope This Helps!
Rich

 

[DaveC]

Do zeners come in both glass & plastic packages?

Thanks.

 

[Ross Herbert]

o zeners come in both glass & plastic packages?
:
:Thanks.


Yes they do..

 

[Josepi]

Even without the "variable" this can work. Use a high enough DC voltage.

There is a method with a scope, resistor and AC supply but it is much more
complex for a novice (assuming)

0.58 v-drop.

How to check for Zener PIV?

Variable DC supply, 1 meg resistor, series circuit with diode reverse-
biased. Watch the diode voltage as you increase the supply voltage.
When it levels off, you've reached reverse breakdown.

Hope This Helps!
Rich

 

[DaveC]

Even without the "variable" this can work. Use a high enough DC voltage.

There is a method with a scope, resistor and AC supply but it is much more
complex for a novice (assuming)

I got the scope, resistor(s). Variac + small transformer = variable AC
supply.

So describe away!

Thanks.

 

[Rich Grise]

Do zeners come in both glass & plastic packages?

Not simultaneously. ;-P

Cheers!
Rich

 

[DaveC]

I may have the answer, but No, I can't help you....

???

 

[Josepi]

hmmmm... Now you are pushing my memory hard!!...LOL

Let's see.

Make a series circuit with the resistor (R) at the top and the component at
the bottom. Feed the whole thing with an AC voltage supply, top to bottom.

You will need a scope with horizontal input as well as the usual vertical
input and a floating ground or full differential input somwehere. (you work
out the logic .. maybe a floating AC voltage supply would be enough)

Hook the vertical input across the resistor and the horizontal input across
the component. Maybe the grounds together in the middle of components and
floating supply are good for that??? Been a few years.

Now your vertical trace on the scope indicates current (IR drop in the
resistor).
The horizontal trace indicates voltage drop across the component.
You will get the single curve of a component tracer on your scope.

***Component curves***
**shorted = vertical line
**open = horizontal line
**resistor same as R = 45 degree line
**capacitor = circle... me thinks round indicates matching impedance with R
at 60Hz??
** inductor = circle same as cap above??
**zener no current at lower voltages = horiz. line; no voltage increase at
higher voltages = vertical line = visible knee at zener voltage - use
calibrated scales for measurement
**avalanche diode = horizonatal line with foldback and shows current
(vertical at higher end)

Try it! So simple it stinks but is very visible clue. Watch your scope
grounding.



I got the scope, resistor(s). Variac + small transformer = variable AC
supply.

So describe away!

Thanks.

 

[Tim Williams]

Not simultaneously. ;-P

What about glass passivated, plastic package diodes? ;o)

Tim