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  • Users: perts
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  1. perts

    Flex Circuit Tear Protection

    I have a flex a circuit that experiences a tear during exterme stress conditions. Is there something I can do to the flex circuit to prevent it from tearing without redoing the design. I am not in the position to do a relayout or change the geomoetry of the flex circuit. Is there something...
  2. perts

    Low Consumption Latching Circuit

    I am looking to make a very low consumption current led button just like in the picture below. The switch is a momentary switch. I want to press on to turn the led on and then press off to turn of the led. Simple latching circuit. Do you guys how these cheap button led flashlights work...
  3. perts

    High Rate Application with Primary AA Cells

    I have an application that requires a high rate current up to 8A for 1 second numerous times. Most primary cells are not rated for that high pulse current. Is there a way to overcome that. Could I use a capacitor in parallel to provide that current?
  4. perts

    low voltage reverse battery protection

    I have 3 strings of lithium batteries. 4S3P. I need to protect each string from reverse protection and charging. What is good method to this that has a very low voltage drop, less than 100mV at 2 amps. I look at schotkey diodes, their forward voltage drop is too high. Using an O-ring...
  5. perts

    ptc orientation

    what does the oreintation mark on the PTC mean?
  6. perts

    ESD Cap Sizing

    I am trying to design a circuit with a 8KV contact rating (human body model). I want to use ceramic caps to provide esd protection. I want to see how I should size my caps. Is there a specific forumula/rule of thumb to use to determine the voltage rating and capacitance rating for my caps...
  7. perts

    pinout change connector

    Are there any of the shelf connectors that can change pinouts by twisting them. I am looking to the change wiring configuration on a cable by utlizing a connector in the middle that I can either twist or pull and then twist to change the pinout. For example if I have pin A from one end going...
  8. perts

    allow current in one direction only

    i am making a battery application where i only want the current to go in direction. I dont want to use a diode (too big a voltage drop). Are there ICs/ckt that allow current in one direction only? i have a charger that is charging the battery, i want the charger to source the current to the...
  9. perts

    LED Issue

    I have a micro and sinks the current to a 3.3 V LED via 220 ohms to turn it on. It works but as soon as I put my scope probe on the LED (micro side) the LED doesnt turn on. What can cause that?
  10. perts

    Need regulated 12v output to handle 70A

    I need a circuit that will take in 14 v and put out a regulated 12v with a max load of 70A for 4 minutes. Any ideas of what circuit I can make?
  11. perts

    Scale System to Log Data into Excel

    Does anyone know of a system that I can purchase where I can measure something on a scale and it can automatically put the weight in excel. I need to weigh and record units, but i want to make sure there is no recording error in trasfering the weight from the scale to excel.
  12. perts

    Need a Simple Pass Sticker Dispenser

    Is there label sticker dispenser that will spit out a green pass sticker when and only when the tester deems a pass. So basically I want my tester tied to this label machine and dispense a pass sticker when tester determines that module passed the test. Any ideas would be helpful. Thanks
  13. perts

    Disconnect Bus To Module

    I have a bi-directional 5 volt bus. The bus connects to several other modules in the system. I would like to have some feedback on a circuit design to have the ability to disconnect the bus from a specific module but still be connected to the other modules. Thanks, Perts
  14. perts

    Cutting a PCB

    I have a machine that comes in 2 flavors (single, and dual machine). I want to have one PCB for both types of machine. Is it possible to create a PCB that I can cut when I am building a single machine. I would put the circuitry to control the second machine on side of the pcb that we can cut...
  15. perts

    capacitor blown

    i have relay that drives a inductive load of .6mH. The output of the relay also has a capacitor of 100n to ground. i have noticed that after serveral switching the capacitor is blown (shorted)? do you what could be causing this and why?
  16. perts

    relay coil inductance

    how can i measure the inductance of the relay coil
  17. perts

    SPI bus

    i have spi bus and i need to put caps on that clock line, for esd reasons. what value cap size can i put on that line before i start affecting the clock signal. I want to run the spi bus atleast 1 MHZ.
  18. perts

    crystal info

    i am desinging a circuit with a freescale 9s12 mcu. I have a crystal that i want to use to provide the 8mhz clock. i wanted to know how to calculate the caps (C) on the crystal to get the proper crystal setup. i know you need to worry about trace capacitance and capacitance from the actual...
  19. perts

    inductive motor kick back

    im driving a motor with a FET. I am PWMing it. There is a bunch inductive kick back that is coming back and making my FET real hot. How i do protect against that. Do i use a recirculate diode, if so then where. BATT | __ -PWM---| (N-FET) | -- |...
  20. perts

    resistor in series to micro inputs

    i have seen lot of people put like 100k resistors in series on digital inputs to a micro. why is that? how does affect the digital signal.

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