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  1. KrisBlueNZ

    Capacitive Reactance Circuit

    Sure. I have to temporarily give it a .TXT extension so the forum software will accept it.
  2. KrisBlueNZ

    SP6000 paradox alarm problem

    Well, what do you expect from a paradox alarm? Seriously, what happens if you change some of the zones to open? Do they show closed? In other words, are they just wired the wrong way?
  3. KrisBlueNZ

    PC Speakers malfunction. Need help

    You can use any wire that's not too thin. Yes, a resistor or LED lead is fine. Or you could use hookup wire. If it's stranded, you can strip it and twist it tightly so it won't touch anything else, or leave the insulation on the main part. Make sure you clean the board really well first though.
  4. KrisBlueNZ

    Need help building a basic digital counting circuit.

    Yes, that looks better. I think you need to tie the clock inhibit inputs (pin 2 on each 4026) low. Then it should be good to go!
  5. KrisBlueNZ

    Pioneer H-R100 8 track player

    Hi there and welcome to Electronics Point :-) I like your name! Very cool. What's the model number? I'll do a web search for service information.
  6. KrisBlueNZ

    Need help building a basic digital counting circuit.

    Sorry for the delay. I've marked up your schematic. The red lines show where you have shorted the RESET net to the VCC net, and the blue lines show where you have connected the reset button from VCC to 0V.
  7. KrisBlueNZ

    Capacitive Reactance Circuit

    Right, a reactance of 5.6 kΩ at 60 Hz. It's not a sinewave. But LTSpice will calculate the average for you! Zoom the waveform display so it only contains the stable part of the waveform (because it calculates based on the displayed area) and Ctrl-click the "I(D3)" marking above the waveforms...
  8. KrisBlueNZ

    Strange problem help needed!

    Do the guns have any feature that deliberately prevents them from firing in response to some condition they may have detected? Have a look at the documentation to see if there's any circumstance in which the gun is unable to fire, by design. That may give you a clue as to what it thinks it's...
  9. KrisBlueNZ

    automatic doorbell

    Why don't you try it and see? I didn't design that circuit and I don't offer any guarantees that it will work, with or without any suggestions I make. In fact, even for circuits I DO design, I don't offer any guarantees!
  10. KrisBlueNZ

    How can I measure Quiescent current of LDO's?

    The quiescent current in a regulator is the current that flows into the input, but not out the output. Therefore it must flow through the ground connection. It is also called the "ground current". So, measure the current flowing through the ground lead.
  11. KrisBlueNZ

    Renewable Energy

    That circuit would be right, but you don't need a bridge rectifier, because the motor already generates voltage with a fixed polarity. Just a series diode is enough.
  12. KrisBlueNZ

    pressure sensor to detect vacuum breach - where to buy?

    Sounds like a good idea. But how do you get them into the bag in the first place?
  13. KrisBlueNZ

    Rain Sensor Status

    No you're not thick! It's just some new concepts to get your head around. Yeah, come back to it a few times.
  14. KrisBlueNZ

    Rain Sensor Status

    No, it doesn't matter which side is phase and which is neutral. AC voltage doesn't have a polarity! C1 will always be charged the right way because D1 is connected with its cathode to C1's positive terminal, D1 will only conduct on the half-cycles where the voltage coming in at its anode is more...
  15. KrisBlueNZ

    Rain Sensor Status

    No, that looks good as it stands. The 0V rail (the groundplane) is all connected to one side of the 28V AC input. That just means that the other side, that's connected to the anode of D1, ranges from about +36V to -36V relative to that 0V rail. D1 couples this voltage onto C1 and conducts...
  16. KrisBlueNZ

    powering a windshield wiper motor - please help me out on this one.

    I'm hesitant to recommend no-name products sold on eBay but there are suitable-looking units there: http://www.ebay.com/itm/To-DC-12V-10A-20A-30A-Regulated-Transformer-Power-Supply-Adapter-For-LED-Strip-/291213105262?pt=FR_MaisonJardin_Luminaires&var=&hash=item43cda7586e...
  17. KrisBlueNZ

    automatic doorbell

    The relay coil voltage should be 0V when no ultrasonic signal is detected. To fix that, try changing R15 from 33Ω to 3.3 kΩ and adding a 1kΩ resistor between the base and emitter of Q5. Also there should be a capacitor - say 0.1 µF - in series with R13.
  18. KrisBlueNZ

    pressure sensor to detect vacuum breach - where to buy?

    Is an electronic solution the best option? How about some kind of chemical-based indicator that changes colour when it absorbs moisture? Or something else like that? Have you done your due Google diligence?
  19. KrisBlueNZ

    PC Speakers malfunction. Need help

    You're right, those resistors should both be red-red-gold-gold, 2.2Ω. The one that's red-red-green-green doesn't look like the colour bands have changed; they look very even all the way round. My guess is that the wrong component was installed at the factory. Those resistors, and the two...
  20. KrisBlueNZ

    74HC393: 4-Bit Counter in need of debounce?

    It's odd that the collector of the multivibrator transistor goes to 5.5V... It's running from a 5V supply, right? There's nothing in the circuit to generate a continuous voltage higher than the supply voltage. So is the supply voltage really 5.0V? If it's 5.5V that might possibly be causing the...
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