Search results

Search Forums New Posts
  1. KrisBlueNZ

    IC voltage comparator

    Hi Arul and welcome to Electronics Point :-) Thank you for giving a thorough problem description and a schematic in your first post. This is VERY helpful! The LF311 and LM311 are very similar. The main difference is that the LF311 has FET inputs, which have a much lower input current than the...
  2. KrisBlueNZ

    LM324 op amp

    You probably should have a decoupling capacitor between pins 4 and 11 of the LM324. A 10 µF electrolytic in parallel with a 0.1 µF ceramic is good. This will help the amplifier to be stable. Your first circuit has the op-amp inputs mislabelled. The pin numbers (2 at the top and 3 at the bottom)...
  3. KrisBlueNZ

    What are these things?

    Right. Yes, I didn't explain it before, sorry. So that wire is connected at both ends, and the thing still doesn't work? As I said, you'll need at least a multimeter if you want to go any further with it.
  4. KrisBlueNZ

    Open collector buffers VS Non Open Collector Buffers

    An open-collector (or open-drain) output is able to pull down to 0V when the output state is logic 0 (low), but does not pull up to the positive supply rail when the output state is logic 1 (high). In the logic 1 state, it simply goes "open", i.e floating. If you connect a "pullup" resistor...
  5. KrisBlueNZ

    What are these things?

    You've done a good job cleaning up the board. None of the components in that picture look damaged at all. You might want to clean up the other areas that you marked in the other photos, and re-photograph them. I don't think there's anything wrong with the small board with the switch and MIDI...
  6. KrisBlueNZ

    What are these things?

    OK, thanks for the link to the other thread. [The threads are now merged into one.] It's really not clear what has happened to the board and the components inside the red circle in the second picture in post #12 in the other thread. Can you clean that area using firm pressure on a cotton swab...
  7. KrisBlueNZ

    Trouble with tribbles.. erm, timers.

    Sorry, I can't help with recommendations for an ATtiny861 programmer. I suggest you make sure that an 8-bit AVR will be up to the task first - using an emulator, perhaps - before you buy a programmer. Also I can't help re VUSB etc.
  8. KrisBlueNZ

    Emergency Power Supply Schematic Diagram

    That's quite an improvement. Here are some random comments. 1. Q3 can't be driven like that. You'll need at least a resistor in series with the base. But to saturate it, you'd need some significant base current. And you need to insert a diode between where Q3's base connects to the input...
  9. KrisBlueNZ

    What are these things?

    Here's what I can tell you from looking at those pictures. I think you've probably figured it out already. The device you've marked "thermistor or ceramic cap" is probably a PTC thermistor - I can see the tops of the letters "PTC" just to the right of it in the first photo. It's probably a...
  10. KrisBlueNZ

    Chip id please help

    Hmm. It's not listed at Digikey, Mouser, Jameco or Farnell/Element14. A Google search found it listed at http://www.aliexpress.com/w/wholesale-act4088.html and http://www.alibaba.com/showroom/ic-components-act4088.html I wouldn't spend too much with those guys though. These dealers are a...
  11. KrisBlueNZ

    ir sensor range

    Can the local shop tell you the part numbers? It's unusual for a shop to sell you parts but not know what they are. Infra-red may not be the best way to detect obstacles. If the obstacle is matte black it won't reflect any light so it will be invisible. John is talking about pulsed...
  12. KrisBlueNZ

    Homemade Charge Controller Idea

    First, you should make a number of corrections to the schematic. Relays are normally named K1, K2, etc or RL1, RL2, etc or RLY1, RLY2, etc. R1, R2 etc are used for resistors. All components should have references. Batteries are normally BT1, BT2 etc. Diodes are D1, D2 etc. Switches and...
  13. KrisBlueNZ

    DC bias voltage VS DC voltage

    Simmon, you haven't even told us what the circuit does yet! What is it from?
  14. KrisBlueNZ

    What are these things?

    You need to give a lot more information. I don't know what you're asking. You have a "logic driven switch" that's powered from a 6V battery? Can you tell us the make and model number of the thing you have, a description of it, and perhaps upload a photo? To upload pictures, click Go Advanced...
  15. KrisBlueNZ

    Trouble with tribbles.. erm, timers.

    I'm pretty confused by your second and third diagrams in post #63. The second diagram shows a matrix of circles, which I guess are LEDs, and squares connecting the 74HC595 outputs to the outputs from buck regulators. What do these symbols mean? I'm also concerned that you seem to be planning...
  16. KrisBlueNZ

    Re-wiring a powered Subwoofer

    Right, I think a +12V rail from inside the subwoofer or from your AV receiver would do the job. Re pin 7, it has no control function. It just goes through the same type of circuitry as the other five audio signals. I don't think there is any gain-control signal. Edit: It looks like the powered...
  17. KrisBlueNZ

    Guitar amp foot switch question

    Great! You're welcome.
  18. KrisBlueNZ

    Voltage conditioning circuit

    You can't "change the existing circuit" since it's built into the module. Unless Bosch have a suggested circuit (which I doubt), you probably won't find a circuit that will implement any of those translations. We don't even have a formula for them. That's why I suggested the microcontroller...
  19. KrisBlueNZ

    Voltage conditioning circuit

    Bosch HFM5: http://download.fiat-bg.org/Books/General_info/MAF/Bosch%20HFM5%20Sensors.pdf It's interesting that the data sheet doesn't give formulas for calculating airflow from output voltage. It just gives a list of points on the curves for various airflow figures. Have you looked for...
  20. KrisBlueNZ

    Peak voltage output for each stage, voltage ramp input

    Each stage of what? Can you post a schematic diagram?
Top