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  1. pgib8

    Power supply voltage dip protection design

    I second the bridge rectifier. But wait, you didn't say what the problem was.
  2. pgib8

    need help creating a circuit (struggling)

    hi. sounds pretty simple, and you will make it even easier on yourself if you utilize microcontrollers (MCU). first the easiest part: IR transmitter (aka plain simple IR LED). The current will need to be limited because once it opens up, it really opens up and happy let as much current through...
  3. pgib8

    Mind-boggling schematic of power supply.

    I came across the schematic of a power supply at my work. The "engineer" that designed it doesn't work here anymore and as far as the company is concerned the design is fine. There was an "anomaly" that prompted my attention. I spent several days trying to figure out what was going on to no...
  4. pgib8

    RF question for multiple transceivers on one antenna

    Hi! I'm thinking about how one would integrate 3 transceivers on a single antenna, in such a way that in TX mode only one transceiver will ever transmit, and in RX mode, all 3 transceivers will be listening on 3 independent frequencies at the same time. Attached is the concept I'm thinking of...
  5. pgib8

    Basic RF transceiver with RF2713 IC

    I don't have this experience but I think you still need to mix your signal with a carrier. Maybe your carrier is 0Hz and you're doing baseband only, I don't know how that would work. I'm also not sure how these low frequencies would work with little antennas. I'm also not sure if you want to...
  6. pgib8

    Isolated Grounds

    are those optocouplers? if so you already have two grounds on each. one is the cathode of the led, the other is the GND for the logic output. so what you have marked as GND should be the same one that goes to the MCU. Thus you don't need to join the two grounds and you can keep them isolated. If...
  7. pgib8

    PWM - pic18f4550 - led + potentiometer

    Forget the library, just write your own code. You will learn so much more, or do you want to be one of these people that do such exciting projects they talk about but in reality they just used a bunch of libraries and copy and pasted some code from the internet? setting up the PWM should take...
  8. pgib8

    child safety in cars

    i have one more to add. a pressure plate on the roof. if the parents leave their child on the roof and put the car in gear the alarm goes off.
  9. pgib8

    Curious inductor question

    Inductors present a higher resistance to higher frequencies. I'm sending a sine wave through an inductor measuring input and output. Strangely the voltage at the output increases with frequency rather than get smaller. The key for this to work is with no load. Even a 30K resistor will stop this...
  10. pgib8

    PCB alternatives

    To make a professional PCB they will need those files and they will create tools from them, such as solder masks. It always costs a lot to get the first PCBs made because of this tooling.
  11. pgib8

    Using pc power supply for subwoofer amplifier, almost there NEED HELP

    i mixed up red and yellow, but yes you know what i meant. tie all black together and gradually add one positive rail at a time and perhaps also try different combinations.
  12. pgib8

    Trouble with multiple voltage dividers

    I just did a quick math and maybe I messed up, but I'm getting 0.14V coming out of the 3rd divider at full battery. So your step-up is shut down when SHDN is low? Why not pull it low via a resistor?
  13. pgib8

    pcb trace, common-mode noise, and murphy

    The panel is most likely mounted on a telephone pole but there are like 50 distribution lines going through it, each one with 250V. Hard to say where they go to but it might very well include motors. So inside the panel there will be PLENTY of noise. Sadly this circuit board doesn’t even have...
  14. pgib8

    Using pc power supply for subwoofer amplifier, almost there NEED HELP

    can you try to hook up just one of the 12v wires for testing? if that works, then add a second. I think it's OK to have all the black ones together, but I'm not sure if the red ones are supposed to come together. Perhaps these are isolated supplies.
  15. pgib8

    pcb trace, common-mode noise, and murphy

    I’m looking at this circuit board that has inputs from a reed switch. Everything is mounted in a panel which contains 240 VAC. The cable for the reed switch is like 6 feet in length and twisted. When I switch current through this panel, the cable I’m talking about picks up noise which I’m sure...
  16. pgib8

    Accelerometer glove for HID development platform

    you might want to try something like kickstarter. I think people on this forum are more interested in solving problems :)
  17. pgib8

    IR Control

    your best bet is to look up existing circuits online and study them. try searching google images for: simple ir control look at the pictures and further investigate the ones that seem simple. for what you're trying to do, you will find a lot of info online.
  18. pgib8

    Sealing a coax end from RFI leaks

    Go check out this thread: http://www.rctech.net/forum/radio-electronics/688396-transponder-design-12.html
  19. pgib8

    Sealing a coax end from RFI leaks

    You could try posting pictures. So are you saying the center conductor of the coax went around a black ring and then it connected to the shield of the cable? It's hard to understand it without know which wire goes where. Imagine a subway station map that just shows the stations but doesn't show...
  20. pgib8

    Need to replace DC gearmotor with a stepper one

    No problem. Check the datasheet of your h-bridge, it may feature internal protection, including temperature. If it does it shouldn't burn out even if it gets overloaded. If the h-bridge is not powerful enough, look into the possibility of using 2 in parallel or just find a different part that...
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