Help identifying components

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

Glass diode with yellow band. No other markings.

Thanks.

Reply to
DaveC
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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

Glass diode with yellow band. No other markings.

Thanks.

Reply to
Josepi

0.58 v-drop.

How to check for Zener PIV?

Thanks.

Reply to
DaveC

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.

Reply to
DaveC

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

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms
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Reply to
Tim Williams

Measures 0.59v drop. So: silicon.

Reply to
DaveC

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

Thanks.

Reply to
DaveC

DaveC wrote in news: snipped-for-privacy@news.eternal-september.org:

You sound like a man who imagines that by scrunchign his shoulders, no-one will mind when he passes annopyingly several times through the same doorway.

And no. To test a zener you need to try a reverse voltage. Try a variable voltage through a 10K resistor. A sine wave off a 30V transformer will do, just look for the clipping voltages on a scope (or DC voltmeter if you add a capacitor in parallel with the diode). Vz equals peak-peak voltage minus about 0.58V. You may also have to remove one end of it from the circuit to be certain.

Reply to
Lostgallifreyan

Lostgallifreyan wrote in news:Xns9DFE5D70DE9FCzoodlewurdle@216.196.109.145:

Evidently my turn to pass annoying through the same doorway...

Scratch that, the rest stands though, you just have to do the test once for each polarity of that diode. (You'll only see both peaks at once if you have a zero-referenced AC voltage, and even then that capacitor idea wouldn't apply, and I made it more complex than it needs to be, you only need to see the zener peak to know...).

Reply to
Lostgallifreyan

AC

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

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

Thanks.

Reply to
DaveC

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

Reply to
Rich Grise

Do zeners come in both glass & plastic packages?

Thanks.

Reply to
DaveC

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

Yes they do..

Reply to
Ross Herbert

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)

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

Reply to
Josepi

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

So describe away!

Thanks.

Reply to
DaveC

Not simultaneously. ;-P

Cheers! Rich

Reply to
Rich Grise

???

Reply to
DaveC

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.

So describe away!

Thanks.

Reply to
Josepi

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

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms
Reply to
Tim Williams

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Michael A. Terrell

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