Help identifying components

Black diode, smaller than 1Nxxx, green band and green test: "R47".
Glass diode with yellow band. No other markings.
Thanks.
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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
Black diode, smaller than 1Nxxx, green band and green test: "R47".
Glass diode with yellow band. No other markings.
Thanks.
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0.58 v-drop.
How to check for Zener PIV?
Thanks.
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On Fri, 24 Sep 2010 21:55:31 -0700, DaveC wrote:

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
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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)
On Fri, 24 Sep 2010 21:55:31 -0700, DaveC wrote:

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
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I got the scope, resistor(s). Variac + small transformer = variable AC supply.
So describe away!
Thanks.
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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.

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Sim this in LTSpice
Version 4 SHEET 1 880 680 WIRE 64 64 -16 64 WIRE 224 64 144 64 WIRE 256 64 224 64 WIRE -16 128 -16 64 WIRE 224 144 224 64 WIRE -16 272 -16 208 WIRE 112 272 -16 272 WIRE 224 272 224 208 WIRE 224 272 112 272 WIRE 112 288 112 272 FLAG 112 288 0 FLAG 256 64 Vout SYMBOL zener 240 208 R180 WINDOW 0 24 72 Left 0 WINDOW 3 -145 31 Left 0 SYMATTR InstName D1 SYMATTR Value BZX84C15L SYMATTR Description Diode SYMATTR Type diode SYMBOL res 160 48 R90 WINDOW 0 0 56 VBottom 0 WINDOW 3 32 56 VTop 0 SYMATTR InstName R1 SYMATTR Value 47k SYMBOL voltage -16 112 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V1 SYMATTR Value SINE(0 30 50) TEXT -50 312 Left 0 !.tran 200m
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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.
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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
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Website: http://webpages.charter.net/dawill/tmoranwms
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On Sat, 25 Sep 2010 00:01:47 -0500, "Tim Williams"

A small spike snubber? 0.58V?
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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.
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I would trace out the circuitry. If you have that, then the type of diode may be obvious. For example if a diode is across a relay coil to eliminate transcients, then any ordinary diode will work. For a circuit for a desolder station, I would expect all the diode would be common diodes, no zeners, no fast switching, no germanium. Just something like a 1N4004.
Dan
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Measures 0.59v drop. So: silicon.
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Does the fact that both show ~ 0.6 v-drop rule out zeners?
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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.
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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...).
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Do zeners come in both glass & plastic packages?
Thanks.
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:Do zeners come in both glass & plastic packages? : :Thanks.
Yes they do..
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On Sat, 25 Sep 2010 17:04:20 -0700, DaveC wrote:

Not simultaneously. ;-P
Cheers! Rich
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