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  1. KrisBlueNZ

    need help with a simple xlr to 3.5trrs cable wiring

    Hi there and welcome to Electronics Point :) I think you'll need a TRRS plug. If the Nexus 5 works with standard headphones, then the TRS contacts are left, right, and ground respectively. The extra ring is the microphone input. So with a TRS plug, you can't connect to the microphone input...
  2. KrisBlueNZ

    Led flikers?

    Yes, you could connect the LED between PGO and 0V, and use a lower pullup resistor value, as long as the current into PGO is less than 10 mA. For example if VCC is 5V, the resistor must be at least 500 ohms. Say you use 560 ohms. When any power rail is outside specification, i.e. "power is not...
  3. KrisBlueNZ

    Designing a Time Delayed Relay

    Two independent Allegro chips? I don't understand the problem. Tell me where this explanation goes wrong. You will have a 220VAC connection from your distribution panel to a 220VAC socket on your wall-mounted box. One side (doesn't matter which) will feed through one Allegro chip on the board...
  4. KrisBlueNZ

    bathroom door automation design - grab a coffee first!!

    Bummer about your knee! Can you walk on it? I'll PM you my email address.
  5. KrisBlueNZ

    Designing a Time Delayed Relay

    Oops - I just realised... two Allegro chips means a lot more load current, so C1 would need to increase to at least 2.2 µF.
  6. KrisBlueNZ

    Designing a Time Delayed Relay

    Sorry for the really slow reply! So are you saying that your 110VAC and your 220VAC supplies have one side in common? So you plan to put the current sensing device in series with that common wire? From your drawing it looks like you have neutral/ground, and two 110VAC phase busses, and there's...
  7. KrisBlueNZ

    Connecting Circuit to 12V Power Supply

    Try this. If the panels are ON when they should be OFF, and vice versa, move the positive wires coming from the panels from connection A to connection C.
  8. KrisBlueNZ

    Auto switch from invert to mains and vise- versa

    Whoa! I bet you take your wedding ring off when you're working on that thing! And use a screwdriver with an insulated shaft. And keep one hand behind your back!
  9. KrisBlueNZ

    Led flikers?

    Are you talking about the PGO (power good output) pin? It's an open drain output, which means it pulls low but needs an external pullup resistor to pull it high when power is good. So you need a pullup AND a buffer. Your simplest option would be: R1: 10k resistor R2: 220 ohm resistor (adjust...
  10. KrisBlueNZ

    How to connect a dual coil relay

    OK, they're using that relay as the reversing switch, and they're using five of the transistors in the ULN2003 as the ON/OFF control. You need a standard (non-latching) DPDT relay like this one: http://www.digikey.com/product-detail/en/8-1393792-5/PB383-ND/291019
  11. KrisBlueNZ

    Rectifier value?

    Yes, that's what I suspected. I would be more comfortable if you traced out that part of the circuit, so we could be sure of how that resistor is connected. Also I'm surprised that there's a small capacitor across it; this makes me suspect that it's not an inrush current limiter. If you're...
  12. KrisBlueNZ

    How to connect a dual coil relay

    Can you post the circuit diagram, or a link to the article? Does the PICAXE need to be able to close the blinds as well as open them? Have we answered your questions? If not, can you restate your questions?
  13. KrisBlueNZ

    How to connect a dual coil relay

    To use Harald's suggestion, you connect the relay contacts in a "reversing switch" configuration (Google it). When the contacts are in one position, the power is applied to the motor one way round, and when they're in the other position, the same power is applied to the motor the other way...
  14. KrisBlueNZ

    LED Flasher help.

    That sounds like Q3 is faulty, or installed backwards, or there's a problem with the signal on its gate. You can check some things. Check the voltage on the gate of Q3, from pin 2 of U5. It should go high when the blue period of the chaser is due, and low when the red and green periods of the...
  15. KrisBlueNZ

    External bell

    As Harald says. Also you need some kind of suppression on the load, to protect the relay contact in the phone. If you're switching an AC voltage directly onto an AC bell, you need an R-C suppressor. If you're switching a DC voltage onto a DC bell or the coil of a relay that controls the bell...
  16. KrisBlueNZ

    Led flikers?

    You can monitor two or three supply voltages using a supply voltage monitor IC. Many of these are designed to generate a reset signal for a microprocessor and also include a power good delay which causes the micro to be held reset until the supply voltages have been stable for a certain amount...
  17. KrisBlueNZ

    Connecting Circuit to 12V Power Supply

    The COM, NO and NC connection names refer to the first picture in post #3. The pictures in posts #8 and #15 don't show the A, B and C markings. They are shown in the auction page you linked to in post #12 but I don't see anything on that page that says what A, B and C refer to. So I can't tell...
  18. KrisBlueNZ

    Series pass voltage regulator not working as expected

    No, it's not normal for the regulator output to increase as you increase the load. Normally it will drop slightly with increasing load current. How much smoothing capacitance do you have after the bridge rectifier? A rule of thumb is 1000 µF per amp of load current, but I would use more than...
  19. KrisBlueNZ

    Series pass voltage regulator not working as expected

    If Q2 is overheating, make sure Q3's collector is connected properly. I would replace Q2 and Q3 with a single Darlington transistor such as a TIP120 (TO-220 package) or at least a BD679 (TO-126 package the same as the BD139 you're currently using as Q3). It will also need a significant amount...
  20. KrisBlueNZ

    Rectifier value?

    I doubt that 10k is an appropriate value for that resistor, but don't just go whacking in some random value until we can figure out what it should be. Did you replace the resistor back at the start, when you first replaced the bridge rectifier? Or have you just replaced it now, when you...
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