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  1. KrisBlueNZ

    Connecting AC and DC grounds on breadboard

    That's generally right. Normally, mains earth is connected to the power supply's 0V rail at the power supply, and propagates through the circuitry 0V rail to the rest of the circuit. The power supply connects into the other circuitry in the power section, i.e. the drivers, because that's where...
  2. KrisBlueNZ

    sioscan atomic clock model#34101 power supply

    But Steve, it is an atomic clock! What else would it be made of? ;-)
  3. KrisBlueNZ

    Wireless Power Transmission help!

    In addition to Steve's excellent answers... Are you intending that L1 and C2 form a series LC circuit? Or is C2 just for DC blocking to prevent saturation? If the former, have you confirmed the inductance of L1? How are L1 and L2 constructed?
  4. KrisBlueNZ

    Connecting 12v dc motor to a rc circuit car

    I wouldn't power the RC receiver from a different voltage from the voltage it is designed for. But you can use a regulator from your 12V supply to drop the voltage down to 6V for the RC receiver. The H-bridge motor driver is explained pretty nicely at...
  5. KrisBlueNZ

    switch 2 VGA outputs from laptops to one projector

    Yes, it's called a rotary switch. These can be expanded by adding wafers, to switch dozens of signals. Here's a suitable 8-pole one at Digikey: http://www.digikey.com/product-detail/en/C4D0806N-A/451-1022-ND/514076 That one is USD 37.00 which I think is pretty expensive for a rotary switch. No...
  6. KrisBlueNZ

    relay to power a 12v bilge pump

    In that case you can use a "low dropout" (LDO) regulator. These can work with as little as 0.5V voltage difference between input and output, sometimes even less, so you could go down as low as 9.5V before the output voltage loses regulation. How much current does the controller need? Do you...
  7. KrisBlueNZ

    hi everybody!

    Hi Juan. Welcome to Electronics Point :-)
  8. KrisBlueNZ

    resistance monitor

    What is this "circuit" that you want to measure? More information please.
  9. KrisBlueNZ

    relay to power a 12v bilge pump

    The simplest option is a 7809 three-terminal regulator. See http://www.maplin.co.uk/p/ts7809cz-1a-positive-fixed-voltage-regulator-to220-case-n37ca That page claims "no external components required" but you should have decoupling capacitors on the input and output as described in the data sheet...
  10. KrisBlueNZ

    relay to power a 12v bilge pump

    Those are voltages across the coil where the relay is guaranteed to turn ON or OFF. If you put an adjustable voltage onto the coil and increase it slowly, by the time it reaches 7.8V the relay is guaranteed to be activated, i.e. its contacts will be closed. Of course you're supposed to put 12V...
  11. KrisBlueNZ

    relay to power a 12v bilge pump

    Here are some recommendations for relays available from Digikey. 1. TE Connectivity VF4: http://www.digikey.com/product-detail/en/1432793-1/PB1773-ND/1236843 USD 2.83; 30A; automotive; chassis mount (via a tab with a hole for a screw); includes the diode. 2. Panasonic CB...
  12. KrisBlueNZ

    Connecting 12v dc motor to a rc circuit car

    That's not what I was suggesting. If you use two SPDT relays, one driven by each side of the existing H-bridge circuit, there's no problem. When the existing circuit drives both outputs low (or both high), both relays are in the same state and no voltage is applied to the motor. Of course, you...
  13. KrisBlueNZ

    switch 2 VGA outputs from laptops to one projector

    You could have a look at http://www.google.com/search?q=KVM+switch+schematic+circuit+diagram&tbm=isch
  14. KrisBlueNZ

    relay to power a 12v bilge pump

    What's the DC supply voltage in the installation?
  15. KrisBlueNZ

    relay to power a 12v bilge pump

    No problem. Have you chosen your relay? If not, what is the supply voltage, and how much current does the pump draw? You said 15~20A, right?
  16. KrisBlueNZ

    Connecting 12v dc motor to a rc circuit car

    Thanks Duke. Sorry about that! I just didn't have much knowledge about torque, RPM, voltage and current, in relation to DC brushed motors. I looked up the Wikipedia article, and now I know a little bit more! I've been working on a design for a buffer stage using MOSFETs. I've come up against...
  17. KrisBlueNZ

    relay to power a 12v bilge pump

    No. A relay coil is not a short circuit. They have a resistance, usually a few hundred ohms, depending on how big the relay is. Bigger gruntier relays have less resistance but they can still be connected straight across the power source - assuming the coil is specified for that voltage. That's...
  18. KrisBlueNZ

    CKP sensor design with comperator

    Are you planning to build this up, or is it just an assignment and you just need to show it working in the emulator?
  19. KrisBlueNZ

    CKP sensor design with comperator

    What's your question, and what are you trying to achieve? Are you worried that the duty cycle of the output waveform is not 50%? If so, you need to make sure that your upper and lower trigger points are equally spaced around the centre (0V) line of the sinewave. That won't happen with that...
  20. KrisBlueNZ

    relay to power a 12v bilge pump

    A light bulb? That won't help. A bulb doesn't create current. It just glows. Yes you need current to flow through the coil of your interposing relay. You connect a power source, through the contact on the controller, to the coil of the interposing relay, and return the other end of the coil to...
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