Search results

Search Forums New Posts
  1. J

    Custom DJ Karaoke Mixer/Scratch Pad/Laptop

    NVM, you must have edited the schematic. The error is not there, looks like it was supposed to be a capacitor after all.
  2. J

    Custom DJ Karaoke Mixer/Scratch Pad/Laptop

    actually I probably stated that wrong. Your pot. (log) is labeled with a capacitance value instead of a resistance value like it should be. Looks like you copy and pasted it, changed the color to red and forgot about the value. :) Nothing critical, but it is a mistake.
  3. J

    Help in deciphering how this DAC thing works.

    I know I am asking a lot, I understand some C but this is pushing my limits. Is there anyone out there that can help me understand this a little more. I have done my homework, for micro-stepping you need to control the current in the motor windings in a certain order. The LMD18245 is a chopper...
  4. J

    Electronics Help Site

    Nice, I bookmarked it. No ads and very well organised material from the looks. Appreciate it.
  5. J

    Custom DJ Karaoke Mixer/Scratch Pad/Laptop

    Your log is a value of resistance, not capacitance. Why don't you just use a schematic/cad app to draw your schematics. Much easier I would think.
  6. J

    not exactly an electronics repair.. need advice

    I would do what duke says and check the resistance across the speaker coil. Make sure that the coil is still intact.
  7. J

    Questions regarding capacitors

    You are talking about ESR? I was looking up HV capacitors yesterday on digikey and there was a laundry list of HV capacitors 1000uF caps that had ESR less then 1Ohm. Most where in the mOhm range. Are you saying that it would be detrimental to the capacitor if it was discharged in this manner of...
  8. J

    Questions regarding capacitors

    Fixed now! http://www.engineeringtoolbox.com/capacitors-energy-power-d_1389.html (C * V * V)/2 == (1/2 * C * sqr(V)) C = capacitance in Farads V = voltage across the capacitor (.00001 * 230 * 230)/2 = .2645J Time for constant power = .2645/52000 = 5uS Seems right to me unless my calculator is...
  9. J

    not exactly an electronics repair.. need advice

    The big black one looks like an inductor, a coil of wire around a ferrite rod. The other two look like capacitors, the black one is a 16V 22uF. The blue one is a 33uF 16V cap. Both look to be Alum electrolytic caps as well. Should be easy to replace these. Are you sure the coil on the speaker...
  10. J

    Questions regarding capacitors

    I am posting this here on request. I started a pm to ask this question since I did not want to highjack another thread at the time, but the information is to good to keep it private so we will just continue this discussion here...
  11. J

    Need some creativity

    What do you consider expensive? Small steppers on ebay come for less then $20 dollars, out of an old scanner even less. You still haven't said how much torque you need. Probably the most expensive cost of a stepper will be the control circuitry.
  12. J

    light bulb question

    Mogul base? They are about twice the size of a typical 100W light bulb. Would help if you had a picture of the bulb and something to compare it to.
  13. J

    1N4148 Logic Diode to Relay

    No actually the freewheeling diode directs the current flow back into the inductor. This cycle repeats till the diode has used up all the stored energy. This will not increase the life of your relay, but it will protect other sensitive parts in the circuit against high voltage spikes. The coil...
  14. J

    SDRAM problem

    http://www.memorytesters.com/ramcheck/rc_adap.htm
  15. J

    battery in an inverter power supply

    You would want a battery. What happens when the sun goes down and you have no battery or the sun goes behind a cloud on a cloudy day? Without batteries you ability to run larger loads is limited to the amount of power your solar panels can provide at any given time.
  16. J

    For Sale: Karma thread.

    I am just curious, what is considered HV? 100+
  17. J

    Looking for IGBT with vgs < 2V

    actually even though I do agree with you, the one thing he has that neither solar nor wind can provide is a constant source. For what he is trying to do I totally applaud his effort. Use energy that is otherwise completely wasted. I would be very interested in seeing how this project ends up...
  18. J

    DRV8811 stepper cntrl/drv alternative

    I found this circuit on instructibles. It uses a TB6560 which from reading the datasheet is rated at a MAX 3.5A per phase. More realistically, I might get 3A per phase output with adequate heatsink. The one thing I do not understand is whether it has microstepping. I believe it does, but they...
  19. J

    DRV8811 stepper cntrl/drv alternative

    So I have come up against another road block. I want to be able to drive some steppers that have ~3A+ current rating per coil. I like the simplicity of the DRV8811 chip because it has everything I need in one package except for the current capability. Things I would like to have or know how...
  20. J

    help with adjustable power supply

    http://www.national.com/mpf/LM/LM317.html#Diagrams The first picture is the typical design for a LM317 VR. See the ground connected to the adj pin, below the variable resistor? If you measure from that ground to the output you should see a voltage. If you follow that wire it connects to the neg...
Top