Search results

Search Forums New Posts
  1. sureshot

    Voltage tolerance.

    Thank you for your help and the formula, thats about the voltage i need. I might as well use 0.5 watt resistors then if the chip has 5% tolerance, just wanted to do away with the trim pot as this tolerance is 20% and my voltage can be fixed so it all looks workable, thanks again for your help. :)
  2. sureshot

    Voltage tolerance.

    Thanks for your help, i'm not sure if these two resistors at 0.25 watts is enough over head. As a newbie to electronics i know they set the reference voltage and output voltage on the chip but not sure if quarter watt resistors can cope with the power of there job in the circuit, it was the 1%...
  3. sureshot

    Voltage tolerance.

    Just a question on the LM317 and its relatives. Can anyone tell me if 0.25 watt 1% resistors can be used instead of 0.5 watt resistors of 5% tolerance. Many thanks for any help. :)
  4. sureshot

    Smart phone charging.

    Thanks for the info fellas, you both answered my questions, the switching regulator is more efficient way to go and don't discharge below 11.70 volts, with this in mind i should be able to construct a portable high efficient charger. Thanks again for your help much appreciated.;)
  5. sureshot

    Smart phone charging.

    Looking for some advice on SLA batterys used for charging. What i am looking to build is a portable smart phone charger with long life between charging the SLA. So its a 12 volt SLA 7.5 Ah dropped down with a linear voltage regulator. My question is can an SLA battery be discharged between...
  6. sureshot

    Panel meters.

    Many thanks guys for your help, much appreciated. ;)
  7. sureshot

    Panel meters.

    Thanks alfa88. So if the meter internal resistances are for the range intended then would i be right in thinking the amp meter will go in series with the load to be, and the volt meter in parallel with + - volts respectively, that's if i've got it right, thanks for your help. :)
  8. sureshot

    Panel meters.

    Hello. I have a problem using panel meters, i plan on using an amp meter 0-3 amps full scale deflection, internal resistance is 20m ohms, the volt meter is 0-15 volts and the internal resistance is 15k, can anyone tell me if the meters need shunt and multiplier ? or is the internal resistance ok...
  9. sureshot

    ID this switch?

    Its probably a one off design i have never seen one like it before, with the orifice to take a push button of some kind. It could well be modding time and create the closest replacement from another tactile switch. Not much help i know but manufacturers often make up one offs for a product...
  10. sureshot

    Old pc power supply alternatives.

    Ok thanks for the ideas i will look it up see what i can find, if not the load resistor is no problem, was just trying to find options to less idle current. :)
  11. sureshot

    Old pc power supply alternatives.

    Thanks for your reply's, so what ive heard on taking a +5 volt wire back to an IC on the low voltage side of the supply is not really needed in terms of newer units, i was just going down the road of a suggestion a friend made on not needing a resistive load but take this so called wire back to...
  12. sureshot

    Old pc power supply alternatives.

    Hello to you all, my first question. What i am trying to find an answer to is if i convert an old pc power supply can i use an alternative apart from the suggested 10 watt 10R or 5R load resistor, is it possible to trick the supply into believing its got a load on the output, i know the above...
  13. sureshot

    Hi from a newbie

    Thanks for the welcome davenn, hope to gain some experience along the way, must say the forum looks very good indeed. :)
  14. sureshot

    Hi from a newbie

    Hello to the community from the UK nice looking site. Looking forward to reading your topics and projects what ever they might be. :)
View older results
Top