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  1. Hero999

    remote controled door 10 second delay

    It does say on the datasheet, see figure 11 on page 10.
  2. Hero999

    remote controled door 10 second delay

    It's on the datasheet. http://www.ti.com/lit/ds/slfs022h/slfs022h.pdf
  3. Hero999

    1-25 volt power supply

    Yes, you're right. The inverting input needs to be connected to the output so the Darlington pair is in the feedback loop.
  4. Hero999

    capacitor and inductor

    Because it takes time for a capacitor to charge and discharge and time for a field to grow/decay in an inductor. Think of an inductor as a flywheel, you can't change the speed of a spinning flywheel suddenly, it takes time to speed up and time to slow down. A capacitor is the opposite of an...
  5. Hero999

    graph of time constant rc network

    Here's a hint: 37% = 100% - 63% So if you have a 1uF capacitor and a 1M resistor in series, the time constant will be 1s. If you start at zero and connect the circuit to 100V it will take 1 second for the voltage on the capacitor to reach 63V, that's 63% of the steady state value. On the...
  6. Hero999

    1-25 volt power supply

    The circuit will give poor regulation because the gain is low. Use a single op-amp and put the pass transistor in the feedback loop.
  7. Hero999

    HI. Basic Circuit Design and Osciloscope and FGEN

    I don't know. The pictures you've posted are far too small to see anything.
  8. Hero999

    2 pin compact fluorescent lamp to 4 pin socket?

    I can assure you a black light will work for PCB exposure - I've done it before with good results.
  9. Hero999

    extending an CFL electronic ballast

    Oh yes they do have filaments. They use a switch startler, like old fluorescent lamps do but it's built into the the fitting. The high voltage pulse is produced by the inductive ballast. There's no danger of that happening. If you try to connect two lamps in parallel, the one with the lowest...
  10. Hero999

    2 pin compact fluorescent lamp to 4 pin socket?

    Those cheap old lamps sound too cheap to be any good. Yes, you need a four pin lamp for a four pin ballast but a 9W ballast won't drive a 36W tube. Why not buy a UV CFL with the ballast built-in...
  11. Hero999

    2 pin compact fluorescent lamp to 4 pin socket?

    Seriously, save yourself the trouble and buy a ballast. The electronic ballast inside the screw fitting CFL will be tailored to deliver the correct current to that lamp. The lamp needs a ballast to limit the current to the correct level, in order for it to work properly.
  12. Hero999

    [answered] about 555 circuit

    RL symbolises a load, whether it be a lamp, relay, buzzer etc. The second circuit is wrong - they forgot the decoupling capacitor; something which is explained on the datasheet.
  13. Hero999

    doubt in active device

    Active components such as semiconductors actually process or control electrical energy. Passive devices such as resistors, capacitors and inductors dissipate or store energy.
  14. Hero999

    capacitor allow dc or ac

    A capacitor always passes AC and blocks DC. However a filter can be made with a capacitor and resistor to allow DC and block DC.
  15. Hero999

    relative permittivity

    http://en.wikipedia.org/wiki/Relative_permittivity
  16. Hero999

    How to choose a high voltage relay

    No, an arc can form when the relay is not switching, if there isn't enough clearance between the contacts. The breakdown voltage in air is typically 1kV/1mm, so for 2kV the gap between the contacts needs to be at least 2mm. A high voltage relay may be filled with a gas or vacuum which has...
  17. Hero999

    How to choose a high voltage relay

    The current rating is not a problem. It's better to go higher than lower. Using a power relay to switch low current signals is only a problem at very low voltages. The problem with using a lower voltage relay is the contacts can arc over and what's worse it it could be unpredictable.The relay...
  18. Hero999

    How to choose a high voltage relay

    Is 2kV the peak voltage? What's your budget? This will not be cheap. There are reed relays which can do this: http://www.gigavac.com/pdf/ds/hv/gr6cba335.pdf Rs and Farnel both sell reed relays which will do this...
  19. Hero999

    PLS HELP US

    How about starting with the part number which is written on the component?
  20. Hero999

    PLS HELP US

    Ever thought of searching for the part number using Google?
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