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  1. KrisBlueNZ

    Replacing a Photoresistor with Triac question

    Hi there and welcome to Electronics Point :-) Thanks for explaining your whole project. This makes it a lot easier for us to understand what you really need. I don't think a triac is what you're after. Triacs are high-power switching devices that can be used to control lamps and motors...
  2. KrisBlueNZ

    Heathkit IP20 Power Supply

    Good. Somewhere in that circuit, the voltage is dropping when you try to draw current from the output. We need to know where that voltage drop is occurring, and fix it. I will explain a bit more below. OK, that's good. That means that the mains transformer, the bridge rectifier (D1~4) and C2...
  3. KrisBlueNZ

    Can you use serial communications on ethernet?

    Are you suggesting a text window like a terminal? So you can type on it and that's sent to the alarm unit through its serial port, and anything it sends back is displayed in a text window? John, how is the alarm unit's serial port normally used? Do you connect it to a terminal and communicate...
  4. KrisBlueNZ

    Python programming course help

    I wasn't being sarcastic, though it might have looked like it. And you're not a slow learner! There's a lot to learn and you're doing well.
  5. KrisBlueNZ

    Python programming course help

    Sure :-)
  6. KrisBlueNZ

    Can you use serial communications on ethernet?

    Would a Raspberry Pi do this? Or a BeagleBone?
  7. KrisBlueNZ

    Help needed quick!

    Great work both of you!
  8. KrisBlueNZ

    Reduce Physical Size of Old Chopper Circuit

    I don't understand what your circuit does because I don't have a general overview of its purpose and how it fits into the system. But don't worry because I don't think I can suggest anything anyway. I suggested synchronous rectification to increase efficiency so you might be able to use...
  9. KrisBlueNZ

    Stage Line 500W amp repair project

    With respect to "T4" which is the 0V rail. The amp uses split supplies which aren't supposed to be that high, but the output transistors aren't fitted yet so there's hardly any load on the power supply.
  10. KrisBlueNZ

    Reduce Physical Size of Old Chopper Circuit

    Nice! I would be interested to see the rest of the schematic. Do you have a description of operation written up? Have you looked into synchronous rectification to improve efficiency? That's probably the only suggestion I can make.
  11. KrisBlueNZ

    Help needed quick!

    It looks like you have a camera with three plugs that plug into a box that converts the signals and sends them over a multi-core cable using a four-pin RJ-11 connector at each end. Are there any other connections to the camera? How does it get power? Perhaps through the red cable? The socket...
  12. KrisBlueNZ

    need help to write simple program

    If you're new to programming, this may not be a good project to start with. It contains a number of separate functional requirements: input capture and debounce, pulse counting, conversion of pulses to a rate, arithmetic scaling, conversion to numeric representation, and multiplexed display...
  13. KrisBlueNZ

    How can µF-range capacitors reduce AC voltage?

    Hi there and welcome to Electronics Point :-) That circuit is called a capacitor-fed power supply. The reactance of the capacitor converts the AC voltage to a current that charges the reservoir capacitor and powers the LEDs. These power supplies are not isolated and are an electric shock...
  14. KrisBlueNZ

    How to Read Relay State using Digital Pin?

    It sound like you want Arduino #1 to be galvanically isolated from all of the Arduino 2 circuitry and the warning light. This would normally be done using an optocoupler or a relay. If the second relay on your board is not used, you can use that. Drive it from the same signal that the first...
  15. KrisBlueNZ

    Can you use serial communications on ethernet?

    That instructable doesn't make the serial port accessible on an Ethernet LAN; it just adapts one type of connector to the other, so you can send serial data over a piece of Ethernet cable! To do what you want, you would need a microcontroller-based board that implements the Ethernet protocols...
  16. KrisBlueNZ

    3D Glasses

    Click here.
  17. KrisBlueNZ

    Help repairing 3M model 101 Bridging Video Switcher

    If you want, upload some photos of the circuit board. Be sure that all of the part numbers on the large ICs are readable.
  18. KrisBlueNZ

    Help repairing 3M model 101 Bridging Video Switcher

    Yes
  19. KrisBlueNZ

    Help repairing 3M model 101 Bridging Video Switcher

    OK it looks like it's a 3M model 101 bridging video switcher. Have you tried Googling those keywords? There doesn't seem to be service information available. If you want, upload some photos of the circuit board. Be sure that all of the part numbers on the large ICs are readable.
  20. KrisBlueNZ

    Stage Line 500W amp repair project

    Yes, there's something odd happeing there. It looks like R108 is shorted out, but I've never heard of a resistor going short circuit. Can you power off the amp, and measure resistance across R108 (in circuit, probes either way round, preferably with Q46 still removed). It should measure about 1...
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