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Tricky Dicky

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Everything posted by Tricky Dicky

  1. The distributors website says they are good for up to 48V but the 1K current limiting resistor for the indicator LED suggests it is set up for 12V. Richard
  2. I would hazard a guess that the resistors you have are 0.125W. For example a standard LED with Vf = 2V and If = 10mA with a 12V supply would require a 1K resistor and the power dissipation would be 100mW(0.100W) so you can see you are very near the ability of the resistor to cope. If you are using white LEDs where the current draw can be as much as 30mA you will make the resistors run hot. I would uprate your resistors to 0.250W or even 0.5W to play safe after all you are wiring them inline with the lamps and it is not as if you are worrying about component space on a PCB. Richard
  3. Andy what is the status of images uploaded to RMWeb by copyright holders? I am thinking of the likes of Brian Lambert who has often uploaded images from his website which also appear in his book. In the past other respondents to the same thread have often reused these images even altered them as part of the ongoing discussion is this still OK? Richard
  4. I am mainly using an iPad Air to access the forum and I am finding I have to tap links twice before the link will open. This is not a problem with other websites I visit just unique with RMWeb. Richard
  5. Does the subscriber discount apply to digital subscribers? Richard
  6. Have you considered PICAXE. Not usually the first choice of PIC due to speed and memory capacity but for what you are planning will easily cope. Plenty of interfacing circuits in the free manuals and cheap to get started. http://www.picaxe.com/ Richard
  7. I would hazard a guess that it is a logic gate astable using something like a 4011 quad NAND gate IC which is a 14 pin IC. Such an astable just requires two of the four gates with inputs linked to become inverters hence why the there are no connections on one side except for the +V pin. If it is a 4011 IC it will be good for up to 15V. The 10K trimmer and the larger capacitor I would suggest are an RC circuit controlling the pulse rate. I cannot figure out what all the other resistors and capacitors are for although one might be across the voltage rails. As someone has pointed out there is a transistor to boost the power output since the IC output is a max. 10mA. I am surprised that the inputs of the other two gates are not tied down to 0V to stop their outputs floating. Richard
  8. Came across those earlier and they look good but it is a US site and they are an eye watering price of $8 each. I can see restorers of antique radio equipment being interested but for a layout? Richard
  9. You want to look in the 4mm sockets section of your suppliers catalogue where you will find variations of these which are basically a 4mm socket but combine a binding post https://www.rapidonline.com/truconnect-4mm-binding-post-with-m4-thread-red-17-0065 but if you after a traditional brass binding post then you will probably be out of luck and the nearest to it will be something like this https://www.rapidonline.com/truconnect-uninsulated-earth-terminal-17-0795 Richard
  10. I have stuck loads of cable trunking with double sided tape and generally it stays put the only times they have detached is when stuck to a friable surface. Unsealed wood is a problem particularly MDF, you just need to seal it with paint or varnish and most tapes will hold. The best type to use is the type with a foam core and the most reliable tapes are the ones used in the double glazing industry for fixing trims my local double glazing materials supplier does a range of widths and thicknesses and cheap too. Richard
  11. It's a while since I dealt with an LS150 but I do recall it does not have a built in CDU as some points decoders do, so assuming you are using solenoid motors it is probably down to a lack of current to shift several points at once. I believe if you have several LS150s the solution is to spread route setting across several decoders. Sorry it is not a very helpful answer. Richard
  12. When looking up switches that only stay momentarily on look for (on)-off-(on) in the description the brackets around the on indicate the action is only momentary. Personally I do not think it is helpful simply monitoring a switch position as it does not tell you if the point has actually moved. Using either an inbuilt switch in the point motor or a micro-switch attached to the point is more accurate but it does mean more wiring. One possible solution to simply show which way the switch was moved is to use a on-off-on switch alongside a (on)-off-(on) switch mounting both close to each other the former for the LEDs such that when you operate one switch you move the other. Richard
  13. Having only watched the video and not read the manual for the megapoints controller it would appear that each channel is activated by taking the input pin to 0V that would lend itself to be being controlled by a PIC microcontroller such as PICAXE or Arduino. It should be a fairly simple process to produce a program so a single switch can be used to produce a sequence of outputs to set a route. Richard
  14. Not according to Kirchhoff's Laws, 6 LEDs each with their own current limiting resistor, all in parallel will result in the total current drawn equalling the sum of all the individual currents. So assuming each LED + resistor draws say 10mA then the total current drawn will equal 60mA. If you then wire your circuit boards in series and connect to a 14V supply then you are creating a voltage divider with 7V dropping across each circuit board. Richard
  15. I am with Smokebox on this and as the OP had not replied we are not sure if we are dealing with LEDs or filament bulbs. The fact the supplier cannot say if resistors are included casts doubt on if they are even LEDs in the first place. I think if the OP gets a multimeter the first thing I would measure is the current drawn by the lamps, grain of wheat/rice bulbs if I remember correctly should draw about 60-80mA. Anything less and it is likely LED. If they turn out to be filament bulbs then before adding resistors to control brightness, wiring a couple in series will reduce their brightness by half only using resistors if the OP wants something between full brightness and half brightness. If they are actually LEDs then having survived the OPs 9V & 12V tests suggests they already have resistors incorporated but maybe not enough so a little experimentation with additional resistors should achieve the correct brightness the OP wants. Additionally checking the output of the power supply will help establish whether it is actually 12V or more. The power supply should be checked under load as many power supplies will give a higher voltage unloaded only dropping down to their rated voltage under typical load. Richard
  16. David I have to admire your tenacity in your anti resistor crusade but I have to ask to what purpose? Most of us will probably power our LEDs using re-purposed wall warts or phone chargers whose voltage inevitably will not match Vf of any LEDs used so will have to resort to using resistors anyway. The few who will use batteries will inevitably ask themselves is it worth risking their LEDs for the saving of a few pence in resistors and a few seconds of soldering. So again I say WHY? Richard
  17. Thanks for pointing out the above. In the past I have been castigated for expressing concerns about the use of Scotchlok type of connectors which are a perfectly capable connector if care is taken to ensure the wire sizes are within the design parameters but can be problematic when wire sizes are markedly different. The only non soldering fast connector I recommend are the Wago lever type, these will grip wires up to 4mm2 and can personally vouch will grip wires down to 7/0.2 having tested such to destruction where the wire shredded before the Wago let go. The only downside is they come at a price! Richard
  18. Here we go again! I am surprised we have got so far into 2019 before this old chestnut has surfaced. I cannot believe we are arguing over a component that costs 1p requires a few seconds soldering and ensures a circuit is correct! Richard
  19. Yes. If you intend to use the same power supply @12V then start with a 1K resistor although I think you will have to double the value to get a realistic light effect. Richard
  20. The short answer is yes. Each 3 LED strip already has a resistor which is why you only require a suitable power source @12V adding further resistance in series for the strip going in the signal box will have the effect of dimming the light emitted. What you cannot do is use less than 3 LEDs per strip. Richard
  21. You should be OK as long as you cut them off the tape in multiples of three where indicated. If you are using them as overall illumination then as indicated you will need a 12V battery. If using them to illuminate the insides of buildings you might want to consider using a smaller voltage battery to give a more realistic light. How long your battery will last will depend on individual cell size. Richard
  22. I can confirm the circuit works, I used BC108 transistors. Richard
  23. I think a much simpler solution just requires TR2 & TR3 and the two 10K base resistors. If you have wired your panel exactly as Brian Lambert has in the circuit you showed. Then connect the Collectors of the two transistors to their respective LEDs in the signal and the emitters to the 0V connection as in Rick-H's diagram. Instead of connecting the 10K base resistors as shown simply connect them directly to terminals D & E on the SEEP PM1. The way the circuit works is that as the switch is used to switch between the panel LEDs it also switches between the transistors which when triggered switch on their respective signal LED. Richard
  24. I don't know if there is still some experimenting going on with the look of the pages but at the weekend a number of tabs appeared in the bottom of the RMWeb banner similarly last weekend but during last week and today they have disappeared. Has the forum developed a "Sunday best" mode? i am using an iPad 2 which is well past it's best, could that be the problem? Richard
  25. Great to see the new Power & Control sub forum, just need to get Computer Control & Automation in here and it will be perfect. Richard
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