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  1. Arouse1973

    LM317 voltage drop

    You are using breadboard which has resistance, skinny wires which have resistance, the LM317 will have a certain internal resistance, this all adds up. You only need 0.6 Ohms of resistance to drop 100 mV at 150 mA. Thanks Adam
  2. Arouse1973

    LM317 voltage drop

    Yep Dave's right. PP3 batteries have about 18R internal resistance. The output will drop to approx. 4.7 Volts when drawing 120 mA. Thanks Adam
  3. Arouse1973

    LM317 voltage drop

    Yes I did think of that, could they really fall that much? I have never loaded one to be honest, I am guessing the Arduino would be drawing a small amount of current maybe 10 mA or so. He might have some additional load on the circuit he didn't mention. Thanks Adam
  4. Arouse1973

    Microcontroller controlled by pushbutton for LED flashlight

    Corrected. Thanks Adam
  5. Arouse1973

    LM317 voltage drop

    Hello How much current is the Arduino drawing do you know? Can you draw your circuit showing the connections or take some close up pictures and post them here. Thanks Adam
  6. Arouse1973

    Microcontroller controlled by pushbutton for LED flashlight

    Regarding the MOSFET I see the error I chose the wrong version of the same part. I'll correct this. Adam
  7. Arouse1973

    Microcontroller controlled by pushbutton for LED flashlight

    1) The MOSFET is one of the ones Kris chose originally. It's doesn't matter really, I just noticed it was a nice small package. We can change it if you want, as long as the one you are using will fit. http://diodes.com/datasheets/DMN1019UVT.pdf 2) Pull up resistor for the switch. It can be...
  8. Arouse1973

    Controller boards for multiple relays

    Ah.. Q was out of the lab, testing his new pen that doubles up as a parachute with laser guided missiles, so 007 had to come here for help. Don't you feel so proud that you could be helping someone from MI6?
  9. Arouse1973

    Need help about RPM Sensor in automotive

    What work have you done so far? You need to choose a processor that you want to use. Then think about the sensing circuitry, Hop @hevans1944 gave you an idea in his post above. Once you have done this we can fill in the gaps for you if you have forgotten anything. You could have ago at drawing...
  10. Arouse1973

    Looking for answers to questions in 2nd edition of the art of electronics

    Hello Robert. I am not sure if they are available, I couldn't find them. Some people are saying the student edition but this doesn't have the answers. It does however have worked examples of its own. Why not post some of the questions on here with your answers stating the page number and the...
  11. Arouse1973

    Help needed with High Current Voltage Regulator Circuit.

    The capacitor value will depend on the type of load transients you get. You could try the capacitor you have and see if it works, as you already have it. Adam
  12. Arouse1973

    Help needed with High Current Voltage Regulator Circuit.

    Hi Rob This is your circuit! I simulated it for you showing you it should work. It's a steady state D.C simulation so the capacitor is not important. Adam
  13. Arouse1973

    Need help about RPM Sensor in automotive

    And the other question? Micro or Digital logic?
  14. Arouse1973

    Microcontroller controlled by pushbutton for LED flashlight

    Here you go.
  15. Arouse1973

    Need help about RPM Sensor in automotive

    Do you want to do this with logic gates and maybe some seven segment displays or using a microprocessor? Adam
  16. Arouse1973

    Microcontroller controlled by pushbutton for LED flashlight

    Looks like there are some good ideas coming out here. Adam
  17. Arouse1973

    Help needed with High Current Voltage Regulator Circuit.

    He is something that might work. Don't worry about the transistor looking a bit different I have added the correct parameters to simulate yours. It stops regulating at approx. 41 Volts. Adam
  18. Arouse1973

    Help needed with High Current Voltage Regulator Circuit.

    No it won't turn off. thanks Adam
  19. Arouse1973

    Help needed with High Current Voltage Regulator Circuit.

    Yes the regulator idea is a good one because just looking at the data sheet for the transistor it looks like you are going to need at least 1 Amp of base current for 100 Amps output. Thanks Adam
  20. Arouse1973

    Help needed with High Current Voltage Regulator Circuit.

    Hi Rob This is an alternative to your regulator if you wanted another option. You said you had considered diodes but could only find a 10 Amp version. The regulator design you have chosen will only regulate to a point which will be when the input falls below the zener threshold. It will actually...
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