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  1. 2

    Has anyone heard of Mikroelektronika?

    hello CocaCola, I was wondering, is it possible to compile our programs with MKE compiler for Pic32 and then debug the program using ICD 3 in MPLAB? thanks
  2. 2

    Has anyone heard of Mikroelektronika?

    hi, has anyone ever used mikroelektronika products such as their compilers and so forth ??
  3. 2

    Can this be done using a JFET?

    Hello KrisBlueNZ, Yes, I know, it's a little foggy... let me review my circuit and I will get back with better details! Thanks for replying.
  4. 2

    Can this be done using a JFET?

    Hi Harald, I really don't need it to be linear, its just to provide a maximum current channel for the the Led to use. I explain below in detail! What you are saying is provide R5 the lowest resistor value according to the maximum range required and use software programming to reduce/increase...
  5. 2

    Can this be done using a JFET?

    Hi Harald, Well, it's not really to modulate the light intensity as this is done by the transistor which its signal is fed from the op amp. The MOSFET (or R5) is really there to provide a maximum range the led can use ... or the maximum current that the led will be allowed to get. You...
  6. 2

    Can this be done using a JFET?

    Hello, Please view attachment OPAMP1. Here is a circuit that works exactly as I need it. This circuit was kindly provided to me by some fellows from this site. The last piece of the puzzle is I need to control R5 from my MCU. I would like to know if R5 can be replaced with a JFET as shown in...
  7. 2

    BJT Ramp?

    Okay, I have managed to trim R3 along with, R1 and R2 and I am able to get exactly: 2.070V->2.5VDC "IN" 1.001V->0.53V "OUT" Which is very acceptable for me! The ONLY problem: R1 = 31.25K R2 = 28.65K R3 = 3.293K Where am I supposed to get these extremely precise resistors? :eek: If I...
  8. 2

    BJT Ramp?

    Bob and Harrald!! I unfortunately need your help once more! My ranges to the op amp were 2.0V->2.5VDC with an output of 1.0->0.5VDC. It was great and it worked !!! The 2.0VDC was fed into my DAC reference voltage via a voltage divider. But now, I am using a voltage reference chip and it gives...
  9. 2

    Potential divider problem

    ah! okay, wow, there's a lot of detail in a circuit like this! I get it now. Thanks KrisBlueNZ. 24v
  10. 2

    Potential divider problem

    Steve, I don't get it, you say: and KrisBlueNZ says: So, steve you must mean that the current coming into a node must equal 0 by taking the highest current coming in the node and subtracting all other currents... no? KrisBlueNZ's way surely affirms the result being correct!! Anyways I sort...
  11. 2

    Potential divider problem

    So, its the resistance as seen from point X ! Got it! One last question KrisBlueNZ. If my 2nd voltage was +5VDC instead of -5 VDC, Vnode would be 6.818 VDC right? Thanks KrisBlueNZ
  12. 2

    Potential divider problem

    Thanks Laplace, I will keep this in mind! One question though: You are using KCL, so isn't the sum of each branch current equal to the total current... so why does the formula equal to 0? If you make it equal to 0 then shouldn't it be: V-(-5)/200 - V-10/100 - V/300 = 0 ? 24V
  13. 2

    Potential divider problem

    Yes thanks for the response, it absolutely makes sense. One other thing though if I may ask, if we pretend R2 isn't there, why are we calculating total resistance of R1 and R3 as though they were in parallel, afterall when we pretend that R2 is not there, aren't R1 and R3 in series and total up...
  14. 2

    Potential divider problem

    KrisBlueNZ, I see how you go the 75ohms by treating R1 and R3 in parallel, but can you please explain how you got the 7.5V??? Thanks
  15. 2

    BJT Ramp?

    Hi Bob, Well, VR4 is 1.507VDC. So I believe that I wouldn't question R3 and R4. Also to avoid confusion, I did not not connected the output of the op amp to anything while doing my adjustments! I tried trimming R1 so that the output is exactly 0.5 when the input is 2.5V. But then when I...
  16. 2

    BJT Ramp?

    Hi guys, I have adjusted my reference voltages to my dac so they are very precise. So the output of my DAC is giving exactly 2.5VDC->2.0VDC. As you know this voltage ramp is fed into the op amp circuit. Out of the op amp as you know, we are supposed to get the following relation: DAC...
  17. 2

    BJT Ramp?

    Wow! Worked the first shot!!! :) Unbelievable! I cannot thank you guys enough! Now, I really want to learn more abpout op amps :D sincere regards 24V
  18. 2

    BJT Ramp?

    Okay Harald, thanks for your advice. Stay tuned... I will let you know if the circuit works!! sincere regrads 24v
  19. 2

    BJT Ramp?

    hi Harald, tomorrow i will go out and buy me a few op amps LM324 pdip. i will also look at some op amp tutorials so i know a little what i am doing here. which other opamp do you suggest i buy to keep in my handy stash? i see often the 741, is this a popular opamp and which others would be...
  20. 2

    BJT Ramp?

    Okay guys, I will use Bob's circuit. A few questions before I build it though... 1) Just to confirm, V1 = +5VDC and V2 = my Vs ramp voltage of 2.0V to 2.5VDC right? 2) No negative voltages are required ... right? 3) LT1006 is the part number of the OPAMP. But I will use the LM324N.... is this...
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