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  1. duke37

    Can I use 2 x transformers?

    The diagram looks reasonable to me. The rectifier diodes are only 1A. A pass transistor shouldn't need to be a Darlington with a gain of 1000, an ordinary transistor with a gain of say 20 should give all the current that you require. Remember that the higher the input voltage and the lower...
  2. duke37

    Cueuing system help please!!

    Depends what parts you want. Maplin, RS, Bowood, Cricklewood Electronics, Farnell. I buy bits fom R.F. Potts, Derby, easy to get to from the train or bus.
  3. duke37

    Light Controller Using 8051

    I am not sure but it looks like there might be 5 pins on the relay. With a resistance meter find two pins with a resistance of say 100 ohms. That is the coil, connect these pins to 12V (9V may do) and listen for the click. The other three pins are the contacts. Two pins will be connected...
  4. duke37

    Wanted: wanted - a copy of certain articles from wireless world Magazine

    You could try vintage-radio.net/forum/ , they have a computer thread.
  5. duke37

    LED Turn Signals - Need Diode Help !!!

    x = ? Choose your pick! The diodes can be 1N4001 to 1N4007 All you want is a 1A diode of almost any type and with a voltage capability of 50V or more for safety. The 1N5400 to 1N5408 are 3A diodes. I looked up the Radio Shack website, put in 'diode' and the first one shown was 1N4001
  6. duke37

    LED Turn Signals - Need Diode Help !!!

    We do not have Radio Shack stores in the UK. Why don't you try their website?
  7. duke37

    Auto NIght Light

    The relay is a good choice here since it can isolate the mains supply from the low voltage DC supply. You can use a triac but the DC supply will be live and needs good isolation from ground or human.
  8. duke37

    Conversion of ohms to Henrys

    Is it possible to convert apples to oranges? Ohms are a measure of resistance to electric current. If using direct current this is as simple as it gets. If using AC current then there can be an effect of resistance and inductance (Henrys). The result is expressed as an impedance and is...
  9. duke37

    LED Turn Signals - Need Diode Help !!!

    Sorry about the wrong number The 1N5400 = 50V The 1N5408 =1000V If your lights take 108mA then the 1A 1N400x series will do. Have you checked the ground?
  10. duke37

    Trying to fix Black and Decker RT650 multitool

    The bulb goes in series with the supply. A switch is provided to by-pass the bulb when full power is required. Sorry about the poor picture, all my camera batteries seem to be flat!
  11. duke37

    LED Turn Signals - Need Diode Help !!!

    If an adjacent bulb lights when it should not, then you do not have a good ground. This is a very common problem. If you still wish to go the diode route, you will need to know the current taken. The 1N500x series will carry 3A.
  12. duke37

    Trying to fix Black and Decker RT650 multitool

    One technique used by those mending old radios is to power through a lamp, this will limit the current and with luck stop components blowing and provide enough voltage to see where the short is. 100W lamp should give enough current to run the motor gently.
  13. duke37

    DC volts regulator

    25 Amps is a lot of current and a lot of heat will be dissipated. Normally, several transitors would be used to lessen the load on each transistor and spread the heat making heat sinking easier. You could consider replacing the two diodes with thyristors, thus chopping the waveform to give...
  14. duke37

    Multiple Spark CDIS Project

    The Tesla addicts use 3000V/mm, this seems to agree with my electric fence voltmeter. An ignition coil may have a spark gap to limit the voltage.
  15. duke37

    How to build a TGATE using discrete CMOS

    The 4066 manages to do this, does it not?
  16. duke37

    PWM to voltage conversion - OpAmp offset.

    The LMC662CN has a specified maximum offset of 4mV. The TLC271 has an offset adjustment. Did you set this?
  17. duke37

    MOSFET power supply?

    Show us the actual circuit that you used. Did the 7812 have no more than 30V input? Does the 555 still work? If you blew R6 then perhaps the ground was missing.
  18. duke37

    thermometer

    You could try using a screened cable (co-ax) to keep out interference.
  19. duke37

    How to measure diesel tank level by pressure sensor, tank area and diesel paramenters

    It is necessary to know if the tanks are sealed or open. If the tanks are open then it is only necessary to measure the pressure at the bottom. Expansion of the fuel will alter the volume of the fuel but not the mass so the pressure will not change with temperature. If the tanks are...
  20. duke37

    need make 48volt 2A power supply

    Put four 12V batteries in series?
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