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  1. KrisBlueNZ

    4 Channel Diversity Controller

    Hi wakesetters and welcome to the electronics point forums :-) That's an interesting problem. No, the circuit you have won't do what you want. There's nothing wrong with tying all the inverting inputs of the quad comparator together; the problem is that there's nothing driving them, so they...
  2. KrisBlueNZ

    Modification of anti-bark control circuit - help please!

    Yes, you might be able to filter the signal. You would need to trace out the schematic though, so we can figure out how to connect the filter. Is the human-audible signal sent through the same speaker that the ultrasonic signal is sent through? AFAIK, usually a special transducer is used for...
  3. KrisBlueNZ

    Alternatives to LDR for audio signal.

    Any kind of VCA (voltage-controlled amplifier) will allow you to vary the amplitude of an audio signal using a control voltage. Do a Google search. A common way to make a VCA is using an OTA, operational transconductance amplifier, such as the LM13700, which contains two of them. Google that as...
  4. KrisBlueNZ

    stepping down voltage twice

    According to John Monks in post #3 on this thread, yes. I don't know personally, because I've never used them without decoupling capacitors! They're available in single (LM311), dual (LM393) and quad (LM339) versions. Well that's good!
  5. KrisBlueNZ

    rain warning device

    Oh you! Call the picture an optical illusion, if you like ;-) LOL
  6. KrisBlueNZ

    Toshiba CRT TV Model 21S1ES- No picture

    Hi Michael, Thanks for emailing me the service manual. I believe the problem must be in the IC marked Q100. This is a 64-pin custom mixed-signal IC that includes a lot of analogue signal processing and a microcontroller. The screen overlay text is generated by IC QT01, converted from RGB to...
  7. KrisBlueNZ

    if there possible for pic to faulty?

    Were you able to program the PIC? Did you verify it? Does it verify correctly now?
  8. KrisBlueNZ

    if there possible for pic to faulty?

    Did you see Bob's post? He says you need to pull the -MCLR pin up. That means, connect it through a resistor (e.g. 10k) to VDD.
  9. KrisBlueNZ

    Does there exist a relay with 2 inputs that triggers to the input with the lowest V

    No, it doesn't do the voltage comparison. Some more circuitry would be needed to compare the battery voltages and make the decision about which one should be switched to the charger. The latching relay is the part that actually DOES the switching. It has a common contact, which would be...
  10. KrisBlueNZ

    rain warning device

    Steve, I don't see it the way you've drawn it. To me, the diagram in post #19 has two sets of interlaced fingers, as Shunhook described. The ones that enter from the left connect through the track at the bottom to the connection point at the bottom right. The ones that enter from the right...
  11. KrisBlueNZ

    Voltage amplification?

    Well, you can boost 1.5V to 5V, but you get less current. The important parameter is power, which is V * I, voltage multiplied by current. A DC-DC converter (boost, buck or whatever) converts one voltage to another, but it introduces losses. Assuming it's 80% efficient, the output POWER is 80%...
  12. KrisBlueNZ

    MOSFET I-V characteristics using Probe station and Agilent's parameter Analyzer

    Yes I see the diagram, but I'm not sure what I'm looking at! Why are there so many traces on the graph? What is the significance of each one? Are they different gate voltages? If so, can you mark the voltages next to the traces? Could you upload the traces you got for the N-channel MOSFET for...
  13. KrisBlueNZ

    Function Generator

    You can use any supply voltage within the 555's specifications. Some of the newer 555 variants have different supply voltage limits so check the data sheet if you use one. The circuit will work better at 12V because the output stage does not swing fully to the rails; there is a roughly fixed...
  14. KrisBlueNZ

    MOSFET I-V characteristics using Probe station and Agilent's parameter Analyzer

    Yes. Click the "Go Advanced" button, and find the Attachments button (top line of the toolbar above the edit window, about 2/3 of the way along). This brings up the Attachments dialog. You can browse for files, then click the Upload button. File size limits are listed. This will show them as...
  15. KrisBlueNZ

    MOSFET I-V characteristics using Probe station and Agilent's parameter Analyzer

    Oh, you're probing a silicon die directly? No, I don't have any suggestions; that's way outside my experience, sorry. If you're just interested in the I-V characteristics of N-channel and P-channel MOSFETs, why can't you use actual N-channel and P-channel MOSFETs instead of a CD4007UB?
  16. KrisBlueNZ

    MOSFET I-V characteristics using Probe station and Agilent's parameter Analyzer

    Can't you connect the appropriate pins together before you connect the probes?
  17. KrisBlueNZ

    Ohm's Law doesn't work - Weird?

    LOL :-)
  18. KrisBlueNZ

    Ohm's Law doesn't work - Weird?

    You're welcome! And I think you might mean serendipitous! Right. Solar cells are still pretty inefficient. You need a large area and bright sunlight if you want to get a significant amount of power from them.
  19. KrisBlueNZ

    rain warning device

    Hmm. There seems to be a large lump of something covering four tracks at the top. If it's conductive, it will make the rain detector report that it's always raining. If you can't remove it, you can disable that part of the board by cutting the second and fourth tracks (counting from the top...
  20. KrisBlueNZ

    rain warning device

    OK, that rain detector is just a PCB with interlaced tracks. If you can upload a photo of the track side, we'll be able to see whether they are protected in any way - tinned, for example. If the tracks are still in good condition, you just need to remake the connections to them. I don't have...
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