Search results

Search Forums New Posts
  1. Kiwi

    timed relay adjustmemt

    I think that you are expecting a bit much of a mechanical relay for the small time intervals that you require. As hevans said "Solenoids (and mechanical relay contacts) are relatively slow things". My suggestion would be to build an electronic circuit with a timer(555?) and a Mosfet.
  2. Kiwi

    12V power supply and 12V battery charger

    Speaking from experience, I bet his ears were ringing for quite a while too!:)
  3. Kiwi

    Forward Current, Forward Voltage, Reverse Voltage...

    There are quite a few Ohm's Law apps. I use a great little program called Electronics Assistant for calculations, http://www.electronics2000.co.uk/
  4. Kiwi

    Been doing it all wrong!!

    Martin, Martin, Martin, I'm afraid you still haven't got it. "12v.psu, diode Vf 3.2v, @350ma . So, 12 - 3.2 = 8.8.. So 8.8 / 3.2 = 2.75 ohms??" Why did you divide by 3.2? R = (Vs - Vf) / If , not (Vs - Vf) / Vf
  5. Kiwi

    Circuit to make Car Head Lamp Brighter?

    There is usually an increase in headlight brightness when relays are fitted. Some cars will have a marked increase, while others will have a smaller increase. Depends on the car's wiring system, and the condition of the wiring. Fitting relays is the first step to take when trying to improve the...
  6. Kiwi

    Noob making a power supply

    The -12v rail on ATX power supplies is usually limited to under 1A, so wouldn't be suitable for your application.
  7. Kiwi

    Been doing it all wrong!!

    R = (Vs - Vf) / If So your first example would be; R = (12 - 2) / 0.02 = 10 / 0.02 = 500Ω For multiple LED's in series, Vf is multiplied by the number of diodes. Vf for your second example would be; 3 * 3.4 = 10.2 R = (12 - 10.2) / 0.02 = 1.8 / 0.02 = 90Ω
  8. Kiwi

    Unknown accessory

    What plug is on the other end? How many wires? Are they shielded? Are they twisted pairs? Any chance of a clear photo?
  9. Kiwi

    Best wall power supply for automotive 12v 1w ioniser module

    Is that 19v measured with no load? I would guess that the voltage will drop when under load. Put a load on it and check voltage.
  10. Kiwi

    Can I drive a 12V water pump with a 3.7V battery and capacitor.

    You got cat trouble?
  11. Kiwi

    Project - Wireless Signal Lights

    The normal method is to fit a trailer socket and wire a light bar into it.
  12. Kiwi

    Best wall power supply for automotive 12v 1w ioniser module

    The voltage in a car is a nominal 12volts, but varies quite a lot during normal operation. Voltage can drop to 10v, or less, during cranking and then up to around 14v when the engine is running. Automotive accessories are made to take these varying voltages without failing. The ioniser will...
  13. Kiwi

    Heat issues with car head unit

    Did you take the photos above showing the internals of your stereo? Is today the first time that you have driven the car since they were taken?
  14. Kiwi

    Heat issues with car head unit

    Can you swap the stereo and pocket around to put the stereo at the bottom away from the vents?
  15. Kiwi

    LDR

    Do your ones require you to switch them on at night and off in the morning? The only outdoor LED lights I have seen are either; 1- Solar cell on top charges the internal battery during the day and the battery powers the LED at night, 2- Connected to an external mains transformer.
  16. Kiwi

    Circuit to make Car Head Lamp Brighter?

    Probably just wired the headlights through a relay. Headlights will be brighter because they will be running at full battery voltage, not a reduced voltage through the car wiring.
  17. Kiwi

    disconnect switches

    Is this a small engine with a magneto type system?
  18. Kiwi

    Light Bulbs in the house keep Burning Out

    Suggest that you ask you neighbours if they are also having bulb problems. Have you checked the power supply voltage is correct?
  19. Kiwi

    Pressure sensor

    As Harold suggested, a normally closed switch that is suitable for water would be the best/simplest idea.
  20. Kiwi

    Light Bulbs in the house keep Burning Out

    As above plus, What type of bulbs are they? Are they all the same type? Is it only one type of bulb causing problems? Are your neighbours having the same problem? Are you in a stand alone house or block of flats/apartments?
Top