Search results

  1. Hero999

    Disadvantage of a Bill acceptor using RGB sensors..

    The disadvantage of a bill acceptor based on an electronic system rather than human vision is it doesn't work and is very easy to misidentify real bank notes af forgeries if they're dirty or torn or pass forgeries if they're very good.
  2. Hero999

    ghost detector circiut

    Have you been at the colloidal silver again? Your circuit is missing some vital components.
  3. Hero999

    transmitting webcam information

    The bitrate depends on the codec used.
  4. Hero999

    Need a switch

    You can get microswitches designed for this kind of thing. A touch lamp doesn't use pressure, it relies on an electrical field.
  5. Hero999

    Electronic Switches

    The  power supply voltage to the digital pot will be need to be > the output voltage of the regulator - 1.25V You could power the digital pot IC from the input voltage to the regulator and it will be fine as long as the voltage rating is high enough.
  6. Hero999

    Electronic Switches

    An SCR will turn on and remain on until the current is interrupted. Solid state relays are much more expensive than just buying a digital pot IC. If you use an SSR, you also need to ensure it has a MOSFET output, not TRIAC which is AC only or SCR which can cause distortion.
  7. Hero999

    200 V DC Power supply....

    Sorry, this an English forum so I don't understand half of what you've said. I think you've got this place confused with a Filipino forum with a similar name. You've not provided enough information: output current, input voltage?
  8. Hero999

    Help with creating a power supply

    You shoudn't need a PCB for this circuit. I use toner transfer to do most of my PCBs but the photo method is higher quality. You'll need a laser printer or access to a photocopier for toner transfer. It's easy, print the design, iron on to the board, soak in water until the paper peels of...
  9. Hero999

    Electronic Switches

    An analogue switch is not a solid state relay, the maximum voltage at either side of the switch cannot be higher than the power supplied to the IC. This is because the switches are made of MOSFETs and the gate drive is not isolated. The schematic is on the datasheeet...
  10. Hero999

    Help with creating a power supply

    The laptop PSU you've linked to isn't powerful enough, the amplifier has an output capacity of 100W per channel @ 90% efficiency (220W total) so you need two power supplies capable of at least 110W each which is why I searched eBay for 120W laptop power supplies. The pre-amp will depend on what...
  11. Hero999

    Electronic Switches

    Four resistors with switches across them would only give 16 positions which is much worse. You can use analogue switches (e.g. the CD4066) but it's better to just by a proper digital pot. IC. You also need to beware that the maximum voltage on the pot or analogue switch can't exceed the supply...
  12. Hero999

    Help with creating a power supply

    A transformer with two 18V secondaries can be used. Connect the two secondaries in series to form a centre tap and connect to a brdge rectifier and two large capacitors to the centre tap. Here's an exmaple: The capacitors need to be very large >10,000μF 35V. The transformer can be 200VA...
  13. Hero999

    Help with creating a power supply

    Firstly, ave you asked the supplier? Have you looked at using two laptop power supplies connected in series to make a +/-24V supply? You need to make sure the output voltage and power is enough, here are a couple I found on eBay which will probably do...
  14. Hero999

    Electronic Switches

    Why not use a digital pot?
  15. Hero999

    LM338 Power Suply Current Regulator

  16. Hero999

    Electronic Switches

    If you don't want mechanical relays then you can get solid state relays. What are you trying to do? There's probably an easier way.
  17. Hero999

    LM338 Power Suply Current Regulator

    That circuit will have very poor regulation because the base-emitter saturation voltage of the 2N3055 will vary depending on the current drawn and the 0.47R resistors will have a significant voltage accross them. Suppose the current draw is 0A and you set the voltage to 12V. Then you increase...
  18. Hero999

    Ac to AC converter - help needed

    You won't be able to maintain 120V with 85V with a transformer, if the heater is overrated for what you need and you've got good temperature control, the lower voltage shouldn't matter. anyway I accept a transformer is not a sensible solution so lets forget about it. There's no easy way to do...
  19. Hero999

    high voltage stuff section

    http://www.electronics-lab.com/forum/index.php?topic=19878.0
  20. Hero999

    Electro Magnetic Pulse

    That's a fairly low powered device and probably has to be right next to what you want to kill. There's a mistake in the schematic, a NPN transistor should be used not a PNP, I think they got the symbol wrong.
Top