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Tricky Dicky

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  1. I think you do need to look at your wiring and make sure it matches the specification of the T-taps you are using. If you are going to the lengths you describe above to make the splice then the long term prospects are that you will have the same issue again as a loose connection between wire core and displacement blade will simply produce a high resistance join similar to rails and rail joiners. IDC connectors are a very simple way of splicing wires but if you do not match your wires to the specs then they can be troublesome. Richard
  2. Got to agree, if you are using 7/0.2 wire which is the equivalent of 24 AWG then even the smallest of the T-taps (Red) will struggle to displace the insulation as its minimum range is 22 AWG. Richard
  3. Yes you can, the sets of solder pads are simply sitting on two continuous power rails going the full length of the strip. The 3V I think you will find will be too low, these strips come in two varieties 24V and 12V the latter being the more common. As someone has already stated they will be quite bright and may need additional resistors to reduce the current to acceptable levels and only experimentation will reveal how much. Richard
  4. I do not know why people insist on trying to run LEDs without resistors, after all they are not the most expensive component neither do you need a vast collection of them. DC voltages associated with model railways tend to be 12V in the main. Other power sources often used such as ex-phone chargers are mostly 5V since all phone manufacturers and tablet makers have standardised on USB charging. Even the forward voltages of LEDs range from just below 2V to around 3.5V and since most modellers choose not to run their LEDs at full power the variety of resistors required is limited as long as the r
  5. No that would not work. All resistors dissipate heat the higher the current the more heat. The more heat needed to be dissipated physically the larger the surface area of the resistor needs to be. It is a fine balance not allowing a resistor to get too hot since that begins to alter the value of the resistor. This is the reason why it is recommended to provide each LED in a circuit with its own resistor thus each individual resistor has minimal heat to dissipate. Going of your figures for your coach lighting of 12.5V supply and 0.33A current draw you would require a resistor value
  6. Due to the DCC voltage being a hybrid AC most multimeters will not read the voltage correctly even on the AC setting, so your voltage numbers are highly likely suspect. Since you need a DC voltage for the LEDs anyway, connect a bridge rectifier to the coach pick ups, then measure the voltage on the output of the rectifier on the meters DC setting. Now a little maths, divide the voltage you have measured by the respective current readings you have for each set of coach lights that will be the value of the resistor you need to put in series with the LEDs. You will probably not get the exact valu
  7. Testing as you go along is advisable, if you get something wrong it usually only means one step backwards to resolve it. Having to check out a whole layout to find where a problem has manifested can be a real PITA. Richard
  8. A simple PIC could be used to monitor the number of changes of state on one input and produce the appropriate outputs even flashing lights. Richard
  9. I will concede that, but had already kind off hinted at that with the guitar string remark. The point I was making was prior to the availability of Wagos, ScotchLok was the only viable non-soldering screwless way of connecting/splicing wires that did not require a specialist tool. It is my opinion that wiring into a loom is probably better done with a ScotchLok but if wanting to take a solderless approach to wiring then I think Wago is superior in that they take a wide range of wire sizes unlike ScotchLok where you have to consider which connector to use in relation to the wires be
  10. Please explain how? You can make exactly the same kind of connection with the appropriate Wago as you can with a ScotchLok with the advantage that a Wago can cope with a greater range of wire sizes. The only circumstance I can see a ScotchLok would be better was if your wiring was strung out like guitar strings. Richard
  11. +1 for Wago connectors, they are far superior to Scotch Lok which are often recommended for quick screwless connections. Wagos will happily connect a wide range of wire from 4mm sq. down to 7/0.2. I can attest to the latter having tested to destruction, I pulled the wire apart before the Wago let go. Do go for the the genuine ones as there are a lot of clones on the market and their properties could be suspect. Richard
  12. I currently use a cheap Maplins 40W iron with supposed temperature control but I could not tell you what the temperature is set at since it is a knob control with a coloured scale going from green -cool, to red-very hot and I find setting it at 3/4 turn is right for me but i think if you can set temperature about 365C is about right. When you say the tips are burning out at high temps are you referring to the tip or the element? I suppose prolonged use at high temp will tend to take it out on an element over time but tips tend to get damaged more by abrasions. Most modern irons hav
  13. The spur should be completely isolated from the rest of the layout ie. both rails and needs its own feed. That feed should go to the centre terminals of a DPDT switch. The main feed should go to the two terminals on one side of the centre terminals and the programming feed to the other two. Just make sure the main feed is connected to the same rails as the rest of the layout otherwise you will cause a short. Richard
  14. Keith has outlined several possibilities, but at the end of the day it is all guess work and you really need to get an accurate reading of the current draw. If as you say you are having trouble finding a point where you can connect your meter in series, why not insert a thin piece of insulating material - plasticard say between one battery terminal and the contact in the battery holder then simply put one probe on the battery terminal and the other on the contact to complete the circuit. Richard
  15. Mike you have made the classic presumption that LEDs are like bulbs in that altering the voltage affects their brightness. LEDs are current driven devices and the series resistor that you get in LED circuits is a current limiting resistor. Hence as Keith has pointed out you need to establish the current draw of the LED circuit and as he has pointed out your meter needs to be in series with the battery and LED(s). As we are looking at 2 AA batteries which should be giving you 3V or 2.8V if they are rechargeable (2.4V seems odd unless the batteries are well used). The LEDs are probab
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