M61A1MECH Posted March 20, 2016 Share #1 Posted March 20, 2016 I picked up some through hole mount style diodes at a local surplus store yesterday, couple of pennies each, so I figured I would just search the internet when I got home , using the info printed on the diode to get the specs. Well no luck, I have searched every which way I can think, I looked at DIGIKEY's website and MOUSER's website both with no luck. Hoping that some ore knowledgeable electronics guru can help me out. Standard bi-axial design (leads in each end) Physical size: diameter 0.197" (5.0 mm), length 0.36" (9.0 mm), black with silver stripe Info on the body: S3A2F SI 8318 I have more invested in time searching for info on them than time to find them in the store. It has now become a quest to find the information more than just idle curiosity. Link to comment Share on other sites More sharing options...
Daveand Barbie Posted March 20, 2016 Share #2 Posted March 20, 2016 That's probably a house number. From what I have been able to find, it is 3A current handling and 8318 refers to the package. If it is a metal case it could very well be a zener and if it is a silicone case, it is most likely power isolation. I wish I could have found more for you. All my good reference books are at home and I am not. Link to comment Share on other sites More sharing options...
bkuhr Posted March 20, 2016 Share #3 Posted March 20, 2016 here ya go http://www.americanmicrosemi.com/information/spec/?ss_pn=S3A2F S3A2F NTE Equivalent NTE576 RECTIFIER SILICON 400 Link to comment Share on other sites More sharing options...
M61A1MECH Posted March 20, 2016 Author Share #4 Posted March 20, 2016 Perfect, thanks guys. Link to comment Share on other sites More sharing options...
Flyinfool Posted March 20, 2016 Share #5 Posted March 20, 2016 Now you have a bunch of isolation diodes for hooking stuff up on your bike. Link to comment Share on other sites More sharing options...
cowpuc Posted March 20, 2016 Share #6 Posted March 20, 2016 Now you have a bunch of isolation diodes for hooking stuff up on your bike. Now ya done did it Jeff,, ya woke me up and perked my interrrest.. If memory serves me from High School lectronics,,,, a diode only allows current flow in one direction,, is that right? If that is right,,, once the alternating current from the alternator on our scoots has been passed thru a diode (rectifier?) isnt it changed forever? Isnt that why everything on our bikes is DC dependent beyond the rectifier?? That point understood - what application would an isolation diode have? Would it be used like a fuse? Not trying to call you out friend,, just looking to learn something Link to comment Share on other sites More sharing options...
M61A1MECH Posted March 20, 2016 Author Share #7 Posted March 20, 2016 Well I can use them to build my light bars, I can use them at $0.10 each (while supply lasts) to replace the ones I have been buying from DigiKey for$0.37 each plus shipping and I get the benefit of poking around this great little surplus shop that just opened in town, check it out https://www.facebook.com/Planet-Surplus-1611291625785081/ Link to comment Share on other sites More sharing options...
bongobobny Posted March 20, 2016 Share #8 Posted March 20, 2016 Soooo, to answer your question Puc, one of the uses is to isolate the brake light command from the turn signals. I had an issue with my trailer converter causing my add on brake lights to blink with the turn signals. Inserting a diode into the proper location fixed that bug... Link to comment Share on other sites More sharing options...
Flyinfool Posted March 20, 2016 Share #9 Posted March 20, 2016 Well @cowpuc you are right, a diode is like a check valve for electricity, allowing current to flow in one direction only. As Bongo mentioned brake and turn signals are a popular place for diodes. I have them in the lights that I put into the reflector on the trunk of my bike. I have that reflector wired to be turn signals, brake light and running light. Since it uses the same LED bulb for both brake and running, so you would use 2 diodes, one in the line from the brake and one in the line for the running light. If you were to hook both lines to the same bulb without the diodes, the running lights power would back feed into the brake circuit keeping the whole brake light circuit energized at all times. The diodes prevent this. The Diodes are used any time you need to combine 2 or more circuits but you do not want the circuits to back feed into each other. There are other places they come in handy also. Especially if you try to retrofit cheap LED bulbs into the turn signals. Link to comment Share on other sites More sharing options...
cowpuc Posted March 21, 2016 Share #10 Posted March 21, 2016 Soooo, to answer your question Puc, one of the uses is to isolate the brake light command from the turn signals. I had an issue with my trailer converter causing my add on brake lights to blink with the turn signals. Inserting a diode into the proper location fixed that bug... Well @cowpuc you are right, a diode is like a check valve for electricity, allowing current to flow in one direction only. As Bongo mentioned brake and turn signals are a popular place for diodes. I have them in the lights that I put into the reflector on the trunk of my bike. I have that reflector wired to be turn signals, brake light and running light. Since it uses the same LED bulb for both brake and running, so you would use 2 diodes, one in the line from the brake and one in the line for the running light. If you were to hook both lines to the same bulb without the diodes, the running lights power would back feed into the brake circuit keeping the whole brake light circuit energized at all times. The diodes prevent this. The Diodes are used any time you need to combine 2 or more circuits but you do not want the circuits to back feed into each other. There are other places they come in handy also. Especially if you try to retrofit cheap LED bulbs into the turn signals. :think:,,, :scratchchin:,,, sort like a back flow check valve in a plumbing system? So,, if a diode is used in an A.C. application,, is the voltage always changed from AC to DC on the other side of the diode? And is the diode "rating" basically stating how much current flow it will resist flow to (did say that right?) - so if you have a 3 amp diode it will work as a back flow check valve up to 3 amps of current flow? Are they rated in voltage too - seems like they would have to be? :crackup:you guys may have opened a can of worms by answering my first question Link to comment Share on other sites More sharing options...
Flyinfool Posted March 21, 2016 Share #11 Posted March 21, 2016 I like canned worms. Diodes are rated for current and voltage. When the diode is acting as a check valve to prevent backflow the current is zero (at least close enough to zero for this discussion) until it hits the max voltage rating where the voltage can overpower the diode and make it flow backwards. Still kind of like a check valve has a pressure rating, if you exceed it you can force back flow, so the amp rating does not matter for reverse current. When the diode has the power flowing thru it in the conducting direction is where the amp rating comes into play. The amp rating the maximum amps that can flow thru the diode in the conducting direction before it will overheat and let out the magic blue smoke that makes all things electric function. Link to comment Share on other sites More sharing options...
M61A1MECH Posted March 21, 2016 Author Share #12 Posted March 21, 2016 cowpuc asked So,, if a diode is used in an A.C. application,, is the voltage always changed from AC to DC on the other side of the diode? Sort of, the diode will only let one half of the sine wave through, so you will get a pulsed or chopped DC signal , to make AC into DC with minimal pulsing or chopping you need 4 diodes in the form of a rectifier bridge. Go here http://newton.ex.ac.uk/teaching/CDHW/Electronics2/SimSheet-02.html and go to milestone 4 to see a typical bridge rectifier circuit. Link to comment Share on other sites More sharing options...
bongobobny Posted March 22, 2016 Share #13 Posted March 22, 2016 But even with a diode bridge you still have ripple! That's where capacitors come into play, they smooth out the ripple because capacitors resist changes in voltage levels. To super regulate AC to DC conversion, you also add a coil, or an inductor into the configuration to resist changes in current level. We cornfusing you yet Puc?? Link to comment Share on other sites More sharing options...
cowpuc Posted March 23, 2016 Share #14 Posted March 23, 2016 But even with a diode bridge you still have ripple! That's where capacitors come into play, they smooth out the ripple because capacitors resist changes in voltage levels. To super regulate AC to DC conversion, you also add a coil, or an inductor into the configuration to resist changes in current level. We cornfusing you yet Puc?? If I am cornfused does it mean I have a capacitor problem in my brain Bongo? I am reluctant to answer that cause I dont want no more surgeries for a while.. I may be confused a little BUT I am thoroughly enjoying the shared knowledge!! Good discussion!! Link to comment Share on other sites More sharing options...
Flyinfool Posted March 23, 2016 Share #15 Posted March 23, 2016 OK, I'll mess with the old puc to. Diodes also have an interesting property to take into account. They will drop up to 1 volt per diode depending on what type they are. Unlike a resistor where there are formulas to calculate the voltage drop based on voltage and amperage, the diode just drops a fixed amount of voltage, common is 0.6V, it does not matter what the input voltage is, it will drop the same 0.6V. So that bridge rectifier that has 4 diodes in series can drop 2.4V. Link to comment Share on other sites More sharing options...
bongobobny Posted March 23, 2016 Share #16 Posted March 23, 2016 Darn Jeff, I thought maybe you would mention the Pi configuration for ripple filtering... Link to comment Share on other sites More sharing options...
cowpuc Posted March 23, 2016 Share #17 Posted March 23, 2016 Darn Jeff, I thought maybe you would mention the Pi configuration for ripple filtering... Pie??? Puc loves pie... Puc wants pie.. Puc NEEDS pie... Puc dont worry about the rippling filter when it comes to pie,, thats what makes Puc a "Pie Butt Rider" - right @bj66? Link to comment Share on other sites More sharing options...
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