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  1. (*steve*)

    How do constant current loads work and how to make one

    12V will give you a lot more design freedom. Your voltage reference could be something as simple as a 78L05
  2. (*steve*)

    Hello, Welcome! (Introduce yourself)

    Welcome!
  3. (*steve*)

    LED burns when oscilloscope is connected to it

    Colin's suggestion is not relevant to the OP's problem.
  4. (*steve*)

    Zenor Diode tests as a regular Diode Can you help?

    That's nonsense. Go with Audioguru's answer
  5. (*steve*)

    Parallel LEDs - resistor needed?

    The op-amp has an output impedance which limits the maximum current. It's works pretty much like a resistor in series with your LEDs
  6. (*steve*)

    Parallel LEDs - resistor needed?

    If you're OK with 3mA per LED then your job is done. At that low current, it could all safely go through 1 LED, so no great risk there either.
  7. (*steve*)

    Parallel LEDs - resistor needed?

    The main issue is that bulbs resistance have a positive temperature coefficient and LEDs Vf have a negative temperature coefficient
  8. (*steve*)

    Parallel LEDs - resistor needed?

    Yes. 7 of them.
  9. (*steve*)

    Need help understanding what this circuit does (urgent)

    There is no way to tell. I suspect that pressing of the keys is associated with solenoid activation and possibly changes in the LED display.
  10. (*steve*)

    Amps measurement of a battery

    the battery specs will tell you the recommended charge current, but roughly speaking: (time to charge in hours) = 1.2 * (capacity in Ah) / (charge current in A) If you wanted to charge it in 24h, the current would be approximately 1.5A
  11. (*steve*)

    rgb led specs & control

    Check the resource on driving LEDs. If you have any more questions, please ask.
  12. (*steve*)

    impose current ceiling

    As long as each mosfet is on a different heatsink (or you're just using a single mosfet) you'll be OK for testing. They shouldn't get too warm. They should dissipate about half their rated power. Start with just a single 2R2 resistor. This should give you a 320mA limit. Design for the...
  13. (*steve*)

    Obsolete Hewlett Packard Transistor

    It is called hp_agilent_equipment, it is a yahoo group, but I can't verify it still exists at the moment.
  14. (*steve*)

    Obsolete Hewlett Packard Transistor

    There is mailing list dedicated to repair of old HP and Agilent hardware. Of you're not familiar with it I'll look out up. It was a Yahoo group from memory.
  15. (*steve*)

    Wanted: need an installer in Oakland

    Will you pay for my travel to Oakland? I'm only 16,000 km away. I prefer business class.
  16. (*steve*)

    Advice on splitting voices

    Google "bandpass filters"
  17. (*steve*)

    impose current ceiling

    Sounds good. Have you done any heat sink calculations?
  18. (*steve*)

    Trying to find a Philips Bulb

    You need to know the voltage and wattage. It should be written on the old bulb. If you have no old bulb you can (very carefully) measure the voltage on the socket and then choose a wattage that is bright enough.
  19. (*steve*)

    impose current ceiling

    After a digikey search I'd recommend a IPA50R199CP It has an insulated tab which will make it easier to place these on the same heat sink. Otherwise you'll need insulating mounting hardware.
  20. (*steve*)

    Relay switching

    the diode must be reverse biased across the relay coil. the relay should have a 12V coil The mosfet will need to be a logic level mosfet (what mosfet have you chosen?)
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