Search results

  1. A

    Delay Relay

    What would be the right sort of relay to delay turning on a circuit for a couple of seconds? would I be better off with a 555?
  2. A

    automatic switch

    Would any T0126 transistor work? I'm using multi sim and it doesn't have BD438 or BD436. It does have BF470/BF471
  3. A

    automatic switch

    Thanks
  4. A

    automatic switch

    Thanks, Is there a formula for the Resistors? Is there a specific transistor you would recommend?
  5. A

    automatic switch

    It's for a smart phone. i'll have to upload the schematic later. When the bike gets going, the voltage builds up. when it gets to 5V the phone starts charging but then a few seconds after an error message appears saying the device isn't compatible. rather than have to reach down and manually...
  6. A

    Raspberry Pi

    I recently purchased a raspberry pi computer and I've thought about trying to make it mobile by using a battery pack etc. does anybody know the current requirements for it?
  7. A

    automatic switch

    i had thought about adding a switch in between the alternator and the circuit but its fiddling trying to find it when i'm cycling that put me off the idea.
  8. A

    automatic switch

    the alternator/dynamo is connected to a bridge rectifier so the circuit is effectively DC and i have a regulator keeping it to 5V. Frequency depends on my speed and that will obviously vary. after the first stroke the voltage is right and stays right till i stop, speed doesnt have a noticeable...
  9. A

    automatic switch

    It's a circuit that runs from a dynamo on a push bike. Obviously the dynamo will take a second or two to get up to 6+ volts. But my circuit only works when the voltage is above 5V because the device doesn't accept it at first you have to plug it in when you’re moving which can be a bit dodgy.
  10. A

    automatic switch

    please could you help? i need a circuit that will block voltage lower than 5V is there a specific component for this or will i need to build a sub-circuit? [/SIZE][/SIZE]
  11. A

    automatic switch

    What it is, is I have a circuit attached to a dynamo on a push bike. As you'd expect it takes a second or two to get up to 5V. It needs to turn on the circuit when it gets to 5V and stay on till I stop moving
  12. A

    automatic switch

    It could be either, it's running of an AC dynamo which is then rectified to DC. I have a regulator stopping it going over 5V so when reached is probably what I need. Thanks
  13. A

    automatic switch

    Is it possible to buy or build a switch that will turn on a switch automatically when it reaches 5V?
Top