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  1. KrisBlueNZ

    Battery Powered Power Supply

    It should work fairly well. Check your connections. Also you haven't made the changes to the FET yet, and you should test with the Set and Reset inputs both grounded.
  2. KrisBlueNZ

    N channel high side switch

    Oops I was wrong about that. As long as the bootstrapped voltage rail is capacitively referenced to the source of the high-side MOSFET and the capacitor is charged from a suitable ground-referenced supply (e.g. +15V) you will be OK. But of course you need a high-side driver that's either fully...
  3. KrisBlueNZ

    Battery Powered Power Supply

    The second one will work if you connect R13 from CLK to GND as I described.
  4. KrisBlueNZ

    Battery Powered Power Supply

    Breadboarding and prototyping is only a tiny fraction of the unit sales, and it wouldn't make sense for manufacturers to take on that burden when it's relatively easy for users to use breakout boards (available from many sources) or make quick-turnaround prototype PCBs. Just not economically...
  5. KrisBlueNZ

    How to not hear Mylie Cyrus when I am playing guitar?

    Don't worry about j. The important part of the formulas are: XC = 1 / w C XL = w L where w is 2 pi f (and f is frequency in hertz). So those formulas can also be written XC = 1 / (2 pi f C) XL = 2 pi f L where f is frequency in Hz, C is capacitance in farads, and L is inductance in henrys...
  6. KrisBlueNZ

    N channel high side switch

    BobK is right. If you use a bootstrap capacitor to make a charge pump to generate the high positive rail, its voltage will be 600V above the top MOSFET's source voltage and that will blow the snot out of the MOSFET. Also a charge pump will only work if the MOSFETs are being switched regularly...
  7. KrisBlueNZ

    Simple transistor circuit problem

    Right. You can't "latch" the voltage across the capacitor by feeding the voltage from the emitter back to it. The emitter voltage is about 1.3V lower than the base voltage. That's not the only reason. What you're looking for is a "sample and hold" circuit, where the capacitor can hold its...
  8. KrisBlueNZ

    Battery Powered Power Supply

    I've responded to Greg via a PM suggesting he could stick to the original idea - pushbutton drives clock directly with a pulldown resistor (no capacitor), and a delay of a few hundred ms from q-bar to D. This will debounce the button but its behaviour is not as tidy as the Schmitt trigger...
  9. KrisBlueNZ

    How to not hear Mylie Cyrus when I am playing guitar?

    Not exactly. The impedance of the pickup is more important than its DC resistance because the impedance is higher than the DC resistance. In fact the impedance _includes_ the DC resistance, so there's no need to use the DC resistance in any calculations. And the phasor diagrams relate to phase...
  10. KrisBlueNZ

    Battery Powered Power Supply

    The major problems with that design are (a) R13 needs to be connected between CLK and 0V to provide a pull-down when the pushbutton switch is open, (b) the debouncing available with a single resistor and single capacitor feeding into a clock input that doesn't have a Schmitt trigger...
  11. KrisBlueNZ

    LED driver with current source bias supply?

    AFAIK load dump is a real phenomenon. I'm surprised that your customer expects your circuit to operate as normal during load dump... I would have thought it would be enough for the circuit to just disconnect itself and stop working during the overvoltage.
  12. KrisBlueNZ

    How to not hear Mylie Cyrus when I am playing guitar?

    Yes. But at audio frequencies, the important characteristic of the pickup is not its DC resistance; it is its impedance. This is also measured in ohms at a particular frequency, and is higher than its DC resistance. Both the pickup's impedance, and the resistance added by the volume...
  13. KrisBlueNZ

    How to not hear Mylie Cyrus when I am playing guitar?

    LOL! A pickup is inductive and will form a resonant circuit with the lumped capacitance of the cable. The overall response will have a peak and a rolloff. The volume potentiometer in a typical electric guitar is 100k~500k and its position will have a significant effect on the Q of the tuned...
  14. KrisBlueNZ

    pic outputs to ULN2003A

    This thread: https://www.electronicspoint.com/help-driving-5-inches-7-segment-display-t259371.html seems to be pretty much the same question.
  15. KrisBlueNZ

    Electric/Battery Metronome

    Jen, sorry, I forgot to respond to your question about starting and stopping the metronome. You can probably do that using a thing called a solenoid. It's an electromagnetic device that moves in response to electric current being applied to it. You could probably mount one so that when it was...
  16. KrisBlueNZ

    Help: Driving a 5 inches 7 segment display

    That's right. The digit driver transistors (Q1~4 in your diagram in post #4) are connected as emitter followers. If the voltage supplied to the base is +5V, the emitter voltage will only be about 4.3V, regardless of how high the collector voltage is. Please re-read my post #5 on this thread. I...
  17. KrisBlueNZ

    LM234 current source

    So this is for part of your design in the https://www.electronicspoint.com/led-driver-current-source-bias-supply-t259041.html thread? I posted quite a long response on that thread, which you seem to have ignored. Could you at least do me the courtesy of explaining why you can't use my...
  18. KrisBlueNZ

    LM234 current source

    Do you need to use an LM234? It doesn't look very easy to use. As you say, the data sheet is not helpful for currents above 5 mA, although it describes the device as having a maximum current of 10 mA. The ISET/IBIAS ratio graph seems to indicate that the ratio falls off very sharply around 5 mA...
  19. KrisBlueNZ

    programming help!!!!

    There is a difference between those values: their size. How they are handled may be compiler-dependent. Can you post the compiled code for both versions? Preferably, use my looped version, from post #4 in this thread, because it will be much smaller. Did you try my looped code? Does the choice...
  20. KrisBlueNZ

    Battery Powered Power Supply

    Steve's advice is very good, as usual, but there's another option. In this project, I don't think it's necessary to have a "start back up" condition based on the battery voltage; as soon as an undervoltage is detected, the unit could switch off and only respond to a press of the start button...
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