Model Boat Mayhem
Technical, Techniques, Hints, and Tips => The "Black Arts!" ( Electrics & Electronics ) => Topic started by: mfv1132 on October 27, 2006, 02:57:41 pm
-
I am sure it is fairly simple but I don't want to take any chances,as a new comer to this kind of work, but can someone advise me on connecting Diodes and Resistors.
-
Resistors ore not polarity conscious and so can be connected any way round. Diodes are, and the end of the diode marked with a bar or band should go towards the positive supply line.
-
Thank you Peterm: thats another piece of knowledge i have gained ,thanks to you.
Its because i am old that i am so slow on the uptake, but i get there in the end.
-
It is not always consistant about the identification of the Cathode of an LED - the flat is a fairly reliable indication of the cathode.
The best way is to look at the connections within the diode itself. One electrode is shaped like a cup - this has the diode chip in it. This is the cathode and should be connected to negative.
Tim the Wombat
-
Resistors ore not polarity conscious and so can be connected any way round. Diodes are, and the end of the diode marked with a bar or band should go towards the positive supply line.
Negatory! It's the other way around.
The bar, or band that PeterM mentions, denotes the Cathode end of the diode. The opposite end is the Anode. it is the Anode that should be connected to positive.
Referring to the attachment, figures #1 and #2 show what happens when the diode is forward-biased and reversed-biased.
Figure #3 is the schematic equivalent of figure #1.
Figure #4 pictorial indicates which end of the diode is Anode and which is Cathode. Figure #4 schematic give a good indication of which way conventional current flows. It's illustrated by the diode 'arrow' pointing towards the Cathode. In other words, conventional current flows from the positive rail, through the diode and the lamp, then back through negative.
There are times when the diode needs to be reversed-biased. For instance, where a relay is used (Fig.5). In this instance, it's the Cathode that is connected to positive.
I shan't bog you down with technical howdy-doody, but suffice to say that if you stick by these rules, everything should work good.
-
mfv 1132.
Sorry about that, should have kept my mouth shut. Hope no damage has been caused. Pete M
-
Thank you all for your contributions.Ihaven't carried out any work on soldering the Diodes & Resistors yet :so no damage PETERM.
Can anyone tell me what is the best way of carrying out the work of soldering the Ds. & Rst. so that all the wires are kept in a neat and orderly fashion.
As you will gather from all my queries that i am a novice.
-
The schematic symbol of a diode 'tells' you which way the current will go,
" ->| ", in the direction of the arrow. The "|" is typically the 'band' on one
end of the diode.
- 'Doc
the way things have gone for me this morning, I probably got it backwards...
-
When soldering diodes and resistors capacitors, be as quick as possible with the hot iron as excessive is not what you need, do not twist together, solder them then they cannot lose contact..
Roy
-
dear mfv1132
I've just read your original question - you know, the one about connecting resistors and diodes etc. For what it's worth I can tell you that PMK's answer about which way around diodes go is correct because it actually works on the bench. In reply to your second question about making it neat all I can add - if it's of any use - is to plan to solder your wires and diodes and resistors to a piece of Veroboard, which is copper-backed sheet with conducting strips with holes in them. It gives much better support than just joining things end-to-end in the middle of a wiring run. PMK's circuits are built on this stuff. Check out his website. You can stick the finished mini-circuit board to the inside of your boat with double-sided sticky foam pads.
Sorry if this answer is long. Couldn't get it any smaller without missing things out.
Suit yourself.
-
Dear Full Leather Jacket,
Thank you for your very full and detailed reply ; can you let me have P.M.Ks Web site.
-
Thank you Doc. Wombat & cbr900 for your very helpful advice, Iam slowly getting to grips with the jargon and i will be getting down to putting things into pratice shortly.
-
Dear Full Leather Jacket,
Thank you for your very full and detailed reply ; can you let me have P.M.Ks Web site.
It's in his profile. (Click on his user name in one of his messages or look him up in the members list.)
Doug
-
Talking of diodes and resistors, I have just completed making a regulator for use with your receivers which will work with any receiver making it a BEC, converts your motor power to 6 volts to save the extra battery pack, it is only 25 mm or 1 inch square and weighs only 10 grammes so it will not take up much room...
Roy
-
It's in his profile. (Click on his user name in one of his messages or look him up in the members list.)
Doug
Or...
Members with websites have a globe icon just beneath their main picture. Clicking the icon will take you there.
Roy:
Be interesting to see your BEC. Any chance we could have a looky-see?
On seconds thoughts, we can't attach images to the new server yet. Can it be done via PMs?
Doug:
Welcome home. How was your holiday?
-
PMK,
It would be easier to give you the web address....
http://www.uoguelph.ca/~antoon/ then click on rc gadgets..
Roy
-
PMK
Great holiday thanks, no model boating, although we did get in a whale watching trip - fantastic. Having been back a week I'm ready to go again.
Doug
-
PMK,
There is some interesting stuff on the site is there not...
Roy
-
Well, I envy you.
At least you got to spend a bit of liesurely sight-seeing time.
My boss sends me there regularly. Ten cigarette-less hrs on the plane, followed by another couple hrs waiting around at the terminal... it's a killer!
You step through the airport doors to a world of Californian sunshine, then before you know it , tomorrow is yesterday, and I'm on the next flight back to Blighty.
Dirty Heathrow... rain... cold...
Glad you enjoyed yourself.
Hmm... an incoming from CBR900 as I type.
Standby........
-
PMK,
There is some interesting stuff on the site is there not...
Roy
There is indeed, me ol' cobber.
If memory serves, I think the first project I built from there was his glowplug driver.
Lots of neat stuff on his other pages, too.
Damned if I can see his BEC circuit, though. Would I be right in thinking that you used a standard +5v regulator?
Wanna tip?... Swap out the bog-standard regulator for one of the newer low drop-out types. These work down to around 6-volts or less, whereas a standard reg' will sap as much as around 3-volts from your precious battery juice.
Poor ol' mvf1132... he posted a request for diodes and resistors, and we're talking about everything but!
-
Well, I envy you.
At least you got to spend a bit of liesurely sight-seeing time.
My boss sends me there regularly. Ten cigarette-less hrs on the plane, followed by another couple hrs waiting around at the terminal... it's a killer!
You step through the airport doors to a world of Californian sunshine, then before you know it , tomorrow is yesterday, and I'm on the next flight back to Blighty.
Dirty Heathrow... rain... cold...
Glad you enjoyed yourself.
Hmm... an incoming from CBR900 as I type.
Standby........
PMK
Used to do a job like that many years ago (1970s), sometimes never left the airfield. Great way to see the concrete strips of the world (and sometimes in the dark). OK when you're young, wouldn't want to do it now.
Doug
-
Thank you PMK for your follow up diagram; things are becoming clearer all the time .I wanted to get as much info. as possible before i got down to doing any work.
mfv 1132