Appropriate diode fo my circuit

[EnglishLion]

Hi all,

My name is Tony, I'm from England and I have an interest in both building scale models and electronics. I want to combine the two things with models such as cars that have lighting.

To achieve this, I've designed the attached circuit for it's indicators (or turn signals, as they are known to some) & hazard lights. The question I want to ask is around diodes D1 & D2...

As you can see, I've designed things so that the indicators can be controlled for left & right by Sw2 and the hazards independently by Sw3. In order to prevent power from ghosting from one circuit to the other, I've added D1 & D2. I'm pretty certain that this is theoretically sound as I've read about other applications where this is done but that's the limit of my experience with diodes.

My question is: could anybody help me with what kind of diode would be most applicable in this instance? The circuit will be powered by a standard 9v PP3 battery and IC1 is a 555 timer in Astable mode.

Thanks in advance & Merry Christmas to everyone!

 

[Arouse1973]

Hi Tony welcome to EP, what are the value of resistors for the LEDs?
Adam

 

[duke37]

Any diode in the 1N400x series will do. If you get 1N4007, then they can work up to 1000V.
1N4148 fast diodes can probably manage the current that will be drawn by the LEDs.
Both of these are cheap and will be handy for future projects.

 

[Martaine2005]

Hi Tony the EnglishLion,
Of course you are English! Yor name Tony gave it away!
As suggested above, 1N4148 diodes will be just fine.

Hi Tony welcome to EP, what are the value of resistors for the LEDs?

Also, what leds are you using?

Martin

 

[EnglishLion]

Hi Tony welcome to EP, what are the value of resistors for the LEDs?
Adam

Thanks for the welcome!

The LEDs will either be 3mm round or 0805 SMDs warm-white (to match the old-school bulbs used - first project is going to be a '65 Mustang fastback). As both will be 3.2-3.8v/20mA, the resistors will be 100 ohm.

 

[EnglishLion]

Any diode in the 1N400x series will do. If you get 1N4007, then they can work up to 1000V.
1N4148 fast diodes can probably manage the current that will be drawn by the LEDs.
Both of these are cheap and will be handy for future projects.

Awesome! I had a hunch it would be 4148s but having never used them before, wanted some confirmation. Thank you guys!

 

[EnglishLion]

Hi Tony the EnglishLion,
Of course you are English! Yor name Tony

gave it away!
As suggested above, 1N4148 diodes will be just fine.

Also, what leds are you using?

Martin[/QUOTE]
Lol! Doh, yeah guess telling you where I am from was kinda redundant

Thanks for the advice.

 

[Arouse1973]

All good.

 

[Tha fios agaibh]

Aside from zeners, what types of diodes would not work? The 1n4000 series is the only ones I'm familiar with.

PS; I think of Tony as more of a Roman name. Unless your Tony Blair. Lol

 

[EnglishLion]

All good.

< ----------- Lol and I've also just noticed the lil Union Jack, right about there!!

 

[Martaine2005]

I think I have one too....

 

[EnglishLion]

Aside from zeners, what types of diodes would not work? The 1n4000 series is the only ones I'm familiar with.

PS; I think of Tony as more of a Roman name. Unless your Tony Blair. Lol

Yes, my first reaction to Martaine's observation was 'what's he talking about? Tony is an Italian name.' Until I realised there was an element of sarcasm in it

I doubt Tony Blair knows what a soldering iron looks like. He probably thinks it's something Cherie prepares his clothes with!

 

[Martaine2005]

Quite!!
A smaller version for the smaller leg!

Martin

 

[CDRIVE]

I like the name Tony. Tony's usually like Pizza. I like Pizza. I usually don't like people that don't like Pizza.

I used to be normal but exposure to Marty has been deleterious to my brain!

FYI and I realize that this is off topic but just about any silicon diode would be acceptable in your application.

Marty's Uncle Chris

 

[Tha fios agaibh]

Long ago, Italian immigrants coming to USA, used to all have notes with instructions saying "To NY city"
and upon reading their abbreviated papers at Ellis Island, they often registered their Name as ToNY.

Off topic questions; geranium diodes are not stable enough to use? Are they now considered obsolete?

 

[duke37]

Geranium diodes are very pretty.

Germanium diodes have lower voltage drop than silicon but have more leakage. They are usually used for low voltage applications such as crystal sets. They have largely been superceded by Schottky diodes which have low voltage drop but also more leakage than silicon.

 

[Martaine2005]

 

[CDRIVE]

For crystal radio enthusiasts the venerable 1N34 still reins King today.

Before I moved to EP I was a very active member of AAC. In a thread discussing its characteristics there was an inexplicable dispute regarding its forward voltage drop that I knew to be =<300mV which is typical of Germanium junctions. Anyway, I googled all I could and found an awesome website where a retired EE devoted countless hours experimenting with copious amounts of currently available Diodes, including Schottky's. He presented loads of DC curves as well as recovered RF signal levels vs frequency input for all the Diodes he presented. The test results were astounding because that old bugger kept shining through as Top Dog of the AM broadcast band!

Sometime in the late 60's or early 70's I built the Directional Coupler published in the Amateur Radio Handbook. Many of you will recognize it because it was constructed around copper plumbing fitted with type "N" connectors. As I recall the author makes note of the 1N34 but used a different Germanium (I think) because the coupler was designed to reach high into the UHF bands. Mine tested both impressively flat and directional (-30dB) on an RF sweep generator up to nearly 1GHz!

As years passed and I was able to afford commercial test equipment I purchased a Philco-Sierra 164B for my Land Mobile - Marine Electronics shop but it never left my bench. I found that my old plumbing model handled the rigors and harsh environment of blue water boats just fine. The damn thing never failed to tweak the interest of the customer and was always a topic of conversation.
http://www.machine--tools.com/By-Type-/Lathe-/Sierra-164B-radio-frequency-rf-wattmeter-not-bird.ASPX

Chris

 

[EnglishLion]

Hi guys - happy new year to everyone!

Thanks for the above help with my question. Thought I'd give an update on the project...

I got myself some diodes which worked perfectly so I then designed a circuit for the car's complete lighting and because the single bulbs in the tail-lights perform 4 different functions it required no less than 10 diodes to control the current flow correctly:



I then built this on a proto-board and happily it all worked as I'd planned it, first time! I've put a video of them in action on Youtube:

The video is not the best quality and I'm sure, looking at the diagram, you're probably all thinking 'Oh, you could have done that a much easier way' but considering that just a couple of months ago, I'd never picked up a 555 IC or 4148, I think I've done okay. The only thing I plan to add is some potentiometers to each sub-circuit so that, once installed, I can fine-tune the brightnesses of the LEDs.

Feedback welcome...

Tony

 

[Arouse1973]

Hi guys - happy new year to everyone!

Thanks for the above help with my question. Thought I'd give an update on the project...

I got myself some diodes which worked perfectly so I then designed a circuit for the car's complete lighting and because the single bulbs in the tail-lights perform 4 different functions it required no less than 10 diodes to control the current flow correctly:

View attachment 24311

I then built this on a proto-board and happily it all worked as I'd planned it, first time! I've put a video of them in action on Youtube:

The video is not the best quality and I'm sure, looking at the diagram, you're probably all thinking 'Oh, you could have done that a much easier way' but considering that just a couple of months ago, I'd never picked up a 555 IC or 4148, I think I've done okay. The only thing I plan to add is some potentiometers to each sub-circuit so that, once installed, I can fine-tune the brightnesses of the LEDs.

Feedback welcome...

Tony

Looks good Tony! I think you have done very well considering your initial lack of knowledge. Well done. Are you going to put the LEDs on a PCB and fit them to the car. Would love to see them working in the application.
Adam