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  1. jaylar41

    Forward Voltage of Schottky vs Temperature

    Thanks for the advice. I'll look into the silicon carbide diodes. Hopefully there will be something with a low enough value to work with. The reason I don't use temp sensing ICs is because it's an AC application and I do not want to build a voltage regulation circuit that will supply the...
  2. jaylar41

    Forward Voltage of Schottky vs Temperature

    Hello, I've been looking for a Schottky diode which experiences an increase in forward voltage through the normal operating temperature range (-40C - 125C). I've only seen diodes in which the forward voltage decreases as temperature increases. If such a device existed, I could use it for a...
  3. jaylar41

    LED reverse breakdown voltage

    Thanks guys. My question about the forward voltage may have been a little unclear earlier. Let's forget about the AC example for a moment. Under normal operating conditions, does anyone know if Vf on an LED tends to increase, decrease, or stay the same?
  4. jaylar41

    LED reverse breakdown voltage

    Hello, I'm wondering if anyone has any experience with subjecting an LED to a reverse voltage that is higher than its Vrbd. The specific question would be this: How long before the LED would see catastrophic failure? Most LED datasheets that I've read specify a Vrbd of 5V. Hypothetically...
  5. jaylar41

    Ceramic Capacitor Polarity

    The prototype is on PCB for the most part. At the moment, I've got some wires coming off of the board and connecting to a microcontroller on a breadboard. I'm doing this so that I can re-program the uC often. The connection to the power supply is indeed made with alligator clips right now.
  6. jaylar41

    Ceramic Capacitor Polarity

    The extra diode probably should not have been included with this schematic. I'm using it to separate the rectified signal from the capacitor smoothed signal. I need the rectified signal for some other circuitry on the board. I'm avoiding electrolytics because the application is temperature...
  7. jaylar41

    Ceramic Capacitor Polarity

    Hey guys, here's a basic schematic of what I'm working with. img[http://i8.tinypic.com/24xglfr.jpg] I'm not sure if this is too vague or not. One piece of advice I've read about is that for regulator circuits like this, the designer shouldn't use two ceramics (or non-polarized caps)...
  8. jaylar41

    Ceramic Capacitor Polarity

    Here's a picture that will help What's going on is there is usually 10 pulses of current. In this one though, I've skipped the first 3 illustrating the current being drawn even without me pulsing my circuitry. Can you see how this would affect the result I am seeking. An average of the...
  9. jaylar41

    Ceramic Capacitor Polarity

    The current is measured coming out of the transformer. When there shouldn't be any return current, I see an approximate step function to about 44mA, and after that, it decreases steadily to zero. The zero current is reached at the peak of the sine wave. Then, on the falling edge of the sine...
  10. jaylar41

    Ceramic Capacitor Polarity

    I have not used any software to simulate. That's something I'll have to do eventually I'm sure. The setup is this: I'm using 2 2.2uF ceramic caps with an X7R dielectric. As I said before, these are strictly for filtering purposes. The frequency I'm filtering is approximately 300kHz, and...
  11. jaylar41

    Ceramic Capacitor Polarity

    Thanks for the tips skogs. "Too much current" is as little as 44mA. It doesn't seem like much, but when zero is wanted, then.... The resistance is added to the MLCC as a snubber. As far as when the switching takes place: I am switching throughout the rectified signal. It's a PWM scheme that...
  12. jaylar41

    Ceramic Capacitor Polarity

    Hello, I've got a little problem with a multi-layer ceramic capacitor that I'm trying to use. I'm using some as filter capacitors on a buck regulator circuit. The noise is filtered just fine, but it seems that too much current is conducting through them during their charge cycle (1st half of...

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