Jimbo1707820979 Posted June 28, 2019 Share Posted June 28, 2019 Please help. Query 1. Removing the shielding from the positive very, very fine cable is very difficult for my somewhat clumsy fingers, and the wire is too small for my wire-stripper. What is the best painless way to do this ? So far, my best method has been to burn it off with a match. But this is not very satisfactory. Can the shielding be dissolved chemically ? Or is there another tip ? Query 2. This is a rather stupid one(and I may know the answer already). If I have a 1000 resistor serving 3 lamps will they be less bright or more bright than 1 lamp with its own resistor ? I woul be very grateful for advice. Link to comment Share on other sites More sharing options...
96RAF Posted June 28, 2019 Share Posted June 28, 2019 Wire stripping - try using a scalpel blade on top of the wire and dragged along.Lamps - Look here...are they led or filament bulbs.../media/tinymce_upload/dca2a14b1741cb218fc99eace0536218.JPG If a resistor is controlling the current to three lamps then it will not dim them as much as a resistor controlling the current to one lamp. You also have to take account of if the lamps are connected in series or parallel with each other before the resistor affects them. Chris will likely explain it in more detail for you. Link to comment Share on other sites More sharing options...
Jimbo1707820979 Posted June 28, 2019 Author Share Posted June 28, 2019 They are LED lamps. Purchased in preference to my earlier filament bulb lamps, which got very hot, with accompanying odour. 😮 🫨. Now decommissioned - like the threat to that poor village in Wales likely to be flooded by the sea.Love the cartoon ! Link to comment Share on other sites More sharing options...
Chrissaf Posted June 28, 2019 Share Posted June 28, 2019 Query 1.The method I use to remove the enamel insulation for micro thin wires is to place the wire down flat on a surface. Then whilst holding it down with my thumb, I draw a piece of 'wet n dry' (dry) along the end of the wire to be bared away from my thumb so that the wire is stretched slightly taut. I draw the 'wet n dry' along the wire several times, rotating the wire a little every so often. You can see where the enamel has been removed because the wire gets shiny. Being gentle and taking one's time is the name of the game. Using any form of blade, can make the wire susceptible to breaking..Query 2Subject to applied voltage and resistor values, sharing a resistor may cause the three LEDs to be dimmer..Let's say that the supply is 12 volts and the three LEDs are white LEDs with a 3 volt forward bias..Rob's Ohms Law cartoon tells us that the resistor will have 9 volts across it. The 9 volts will create a current value X. The current value of X will always be the same whether there is a single LED or three LEDs. If there are three LEDs then each LED will only get 1/3rd of the current..For example if the resistor is 1,000 ohms and is only serving a single LED, then the 9 volts across the resistor will draw 9mAThus if the same 1,000 ohm resistor is now serving three LEDs in parallel, then the current for each LED is now only 3mA (1/3rd of 9mA).If you want to still have 9mA for each of the three LEDs, then you would need to make the resistor value 1/3rd of 1,000 ohms (330 Ohms).A 330 ohm resistor with 9 volts across it will draw 27mA, thus 9mA is now available for each LED.However that all said and done, reducing the LED current from 9mA to 3mA will reduce the brightness, but the reduction may not be particularly noticeable to the naked eye. It might be.....it might not be. Link to comment Share on other sites More sharing options...
Jimbo1707820979 Posted June 29, 2019 Author Share Posted June 29, 2019 Chris, thankyou very much indeed. These are great answers and I am now off to find some 'wet n dry' and have a go at the cables. Also, your answer will let me revise my plans for installing the street lamps .BTW I found the simplest way to avoid cables hanging down under the board (no provision having been made during its construction) was to cut 2cm x2cm wood into small lengths, drill a large hole(s) in each, apply wood glue then hold them under the board for a minute or so to set at the required positions. A very cheap method which avoids any crawling under the layout. Better than using staples etc which may be awkward to hammer in. I had intended using the more elegant solution of mini-trunking but this proved impractical. Link to comment Share on other sites More sharing options...
morairamike Posted June 29, 2019 Share Posted June 29, 2019 I use these to secure cables to underside of base board. You can get them cheaper on eBay this is just an examplehttps://www.amazon.co.uk/Adhesive-Mounts-Holders-Multi-Purpose-Length/dp/B077TSNMGD/ref=asc_df_B077TSNMGD/?tag=googshopuk-21&linkCode=df0&hvadid=232061105168&hvpos=1o3&hvnetw=g&hvrand=8619902406698845935&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9045777&hvtargid=aud-543776533562:pla-422207585265&psc=1 Link to comment Share on other sites More sharing options...
morairamike Posted June 29, 2019 Share Posted June 29, 2019 To strip thin insulation hold the wire in a pair of diagonal cutters and grip it gently, then pull. Link to comment Share on other sites More sharing options...
2e0dtoeric Posted June 29, 2019 Share Posted June 29, 2019 For under-board wire 'hangers', I use plain ordinary cup-hooks!An alternative is the favourite zip-tie, just don't pull it tight, then you can thread more wires through later, if needed! Link to comment Share on other sites More sharing options...
96RAF Posted June 29, 2019 Share Posted June 29, 2019 Hot glue gun - sticks wires anywhere you want them. It also peels off fairly easily if you need to. Link to comment Share on other sites More sharing options...
walkingthedog Posted June 29, 2019 Share Posted June 29, 2019 I staple cable ties underneath. Link to comment Share on other sites More sharing options...
BR63 Posted June 30, 2019 Share Posted June 30, 2019 As a supplementary to this thread I have a related issue. I have a 12v DC bus under my deck powering 12v filament platform lamps. Running alongside is my DCC bus. My DCC droppers are connected to their bus by Scotchlok type connectors which work well. However the very thin wires on my new LED lamps will probably be too thin to to connect in that way. As the DC bus is already installed what would be suggestions on how to fix the new LED lamp wires to their bus. Soldering is one option but I am not sure about working in a confined space on my back where control is less than ideal. The bus wire is 7/0.2 gauge. Also what is the best way to strip a small length of the bus wire to allow a conenction to the lamp wire to be mage. Any advice would be welcome. Link to comment Share on other sites More sharing options...
96RAF Posted June 30, 2019 Share Posted June 30, 2019 Solder some thicker wire to each led lamp, insulate with shrink tube and feed this down to your bus and connect in the usual way. Link to comment Share on other sites More sharing options...
walkingthedog Posted June 30, 2019 Share Posted June 30, 2019 Cut the insulation away with a sharp knife. Wire strippers like these are the best way. /media/tinymce_upload/b02a70ac6a2f3641624e759d2d26abae.JPG Link to comment Share on other sites More sharing options...
BR63 Posted June 30, 2019 Share Posted June 30, 2019 Thanks both, I knew there would be an answer or two that would solve it for me! Link to comment Share on other sites More sharing options...
Jimbo1707820979 Posted July 2, 2019 Author Share Posted July 2, 2019 @WTDVery beautiful wire strippers indeed ! But I think I may have to settle fot the 50p stripper my friend got for me at a car-boot sale ! ☹️ How much did they cost, anyway ? (I might weaken). Link to comment Share on other sites More sharing options...
96RAF Posted July 2, 2019 Share Posted July 2, 2019 I bought a matching set of wire strippers and Ethernet/RJ stripper and plug fitter, cost about £40 the pair, but of such quality that I will never have to buy another one. Link to comment Share on other sites More sharing options...
BR63 Posted July 3, 2019 Share Posted July 3, 2019 £13 on Amazon. Great purchase! Link to comment Share on other sites More sharing options...
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