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  1. I

    Printed circuit board: specific heat capacity

    Hi Keith, thanks for the useful links. Those will get me going. According to the table on the webpage of that first link, it's the same as glass. I was expecting something very close to glass but wanted to verify that. Inventor(y)
  2. I

    Printed circuit board: specific heat capacity

    Hi all, I post my question in the Power Electronics section because, to me, this might be the most relevant section. It's about power electronics after all. My question is rather simple. I'm looking for the specific heat capacity of most common printed circuit board materials namely FR4 and...
  3. I

    What ratio for inductances in "LLC resonant converter"?

    Perhaps this app note from on semi might have the answer to your questions. https://www.onsemi.com/pub_link/Collateral/AND8311-D.PDF
  4. I

    Polarity of flyback windings?

    Hi, You can simply check this with a low power square wave generator. Set the freq. to something like 200Khz and connect it to one winding. You can now check the other windings with an oscilloscope. Cheers
  5. I

    2 N type Jfets as ac switch

    How are you driving your fet's? Can you post a schematic?
  6. I

    Relay making MCU hang

    I second elactis repply but also want to add the following: -Also make sure the reset line has a pull-up resistor. (Not a joke, I've seen some people getting nuts because of a floating reset line. A floating reset line can pick up noise.) -You should also connect a varistor across the relays...
  7. I

    Solenoid valve driver

    Hi elactic, you are right about that. I-rms² R losses at low duty cycles will be high indeed. About the reproducible current: the original poster wanted to use a modulated current source for that reason. But ruling hysteresis problems like you describe, can only be done with feedback I think. If...
  8. I

    0->5V DC translator to -6V to +6V

    The only thing you might have to add are some base emitter resistors for Q1 and Q2. 10K will do. This to prevent the transistor from turning due to collector base leakage currents. The base of Q2 is floating when Q1 is on and the base of Q1 is floating when Q2 is on. Biasing into class B or...
  9. I

    replacment components

    I can only comment on the TLC271: an LM358 can also be used here. The 741 and OP07 will not work in your circuit. I don't even have to try. Q1: BC557 2SC668, i don't know if the 2SC2053 will work. For the other parts you mention: i don't know without digging deep into the data sheets of the...
  10. I

    replacment components

    @ Senthilkumar_rjpm you better start reading some basic things about op-amps. The TI app note I've posted I've posted is a good start. With dual supplies the 741 can swing to ground but not the app shown.
  11. I

    profibus Radiated immunity problem

    Changed my post because the answer was not to the point. FvM answer below is to the piont.
  12. I

    Solenoid valve driver

    Hi Frank, indeed. I don't understand why people need an explanation like the one you have given. Shouldn't they be able to design a simple circuit like this all on their own? I think i will stop posting answers to questions like this. People should at least try to find out how to do things and...
  13. I

    replacment components

    -A 741 or OP07 will not work in your circuit. You can use a LM358 instead. It's inputs and output can work close to ground. -For Q1, you can use almost any PNP transistor. A BC557 or something alike will do fine. -The 2SC668 seems to be an RF transistor. Not sure, but an MSPH10 might work...
  14. I

    Solenoid valve driver

    That wasn't clear from what you wrote. -You can use a simple voltage source. The voltage should be set to U= R . I. -Switching the voltage on/off with a PWM signal: use the output of your circuit to drive a mosfet. Fig 8: 8. Power MOSFET PWM Motor Driver Some power PWM drivers for electric DC...
  15. I

    constant current source...!!

    The speed of your circuit depends on the settling time of the DAC and the speed of your op-amp. The capacitor in parallel with the load I suggested would dampen the 150nS ringing/overshoot you where seeing but the capacitor will also increase the settling time of your circuit.
  16. I

    replacment components

    You are right about that. But a TLC271 and a 741 can not be exchanged for the reason I've given above. Why would you use a low bias current (the TLC271 has a dedicated bias setting pin), single supply op-amp if you could have used a cheap 741 instead. I think I posted something about single...
  17. I

    Solenoid valve driver

    Convert the sine wave to an absolute value using some op-amps. for a full description on how to do this: https://focus.ti.com/lit/an/sboa068/sboa068.pdf Option 1: take a micro controller with an AD converter and measure the absolute value. Then you use a timer of the micro to generate a PWM...
  18. I

    Solenoid valve driver

    I can make a quote for this if you want. No really, this is very easy. I know three ways without thinking to hard.
  19. I

    30V DC to +-12 V DC PLZ HELP

    Can you post a schematic? I think you are using capacitive divider or something alike.

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