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  1. R

    Pic interface with sensor

  2. R

    Pic interface with sensor

    Hi, Does this look correct? I have a adustable voltage regulator. This usually has external resistors added to give me the 0.65V DC (i have intentionally left these out). The n channel is connected to the PIC I/O line. A pulse going high low high will give a pulse output as shown. Is there...
  3. R

    Pic interface with sensor

    Thanks Bob, My other question is getting a pulse with that sort of accuracy. Can i get a clean pulse output. I will draw up a schematic Thanks again.
  4. R

    Pic interface with sensor

    I presume my drain will be connected to 0.65V. Does that have implications for the gate source voltage VGS?
  5. R

    Pic interface with sensor

    Thanks again. With the MOSFET as a switch, will there be a delay associated due to capacitance? I was just concerned that the timing may go off and may not be avle to get the 0.1ms.
  6. R

    Pic interface with sensor

    Hi, Thanks for your help. So am i correct in the following 1. Use a adjustable voltage regulator, stepped down to 0.65V. 2. Use a I/O line of the PIC to pulse a FET which is connected to the 0.65V regulator output. 3. Pulse duration is from the PIC using timers? 4. After the pulse has...
  7. R

    Pic interface with sensor

    Hi all, I have attached a datasheet to help in answering my question. It appears that you need to apply a short pulse to the heater 0.65V DC, with specific timing and duty-cycle requirements. Then I need to apply a pulse of power to the measuring circuit of very short duration after the heater...
  8. R

    Pic interface with sensor

    Hi, Thanks for your reply. I am not sure how to design the conditioning circuit. I thought the PWM and LPF was the best method. My other idea was to use a DAC, to generate the pulse of [email protected]. I need to use a microcontroller as after the pulse has been output, i then have to read the...
  9. R

    Pic interface with sensor

    Hi, I have attached a datasheet for a sensor that i am looking to interface to a PIC. Looking at the timing diagram. Is it possie to use pwm + low pass filter to generate the 0.65VDC? Or is there a better method. Could i use a timer to pulse this pwm output line high for 0.1ms, then on the high...
  10. R

    Phototransistor

    Thanks for all your help. Could you recommend any books. I need something that has theory with some practical work on that theory. I think this would be the best solution for me.
  11. R

    Phototransistor

    Thanks for your help. I know my questions seem silly sometimes. But i will do some solid reading. Thanks
  12. R

    Phototransistor

    This is fine. Basically as the light intensity increases the collector current increases. So i get around 2.8V when it is light and around 0.4v when it gets dark. So light mean more current multiplied by my 10K resistor. Hence more voltage. Similarly less current multiplied by the 10K means...
  13. R

    Phototransistor

    Thanks for the replies. I just wanted to know how to calculate the gain ratio of such a circuit and relate this to the voltages i am seeing. Is there a simple calculation? The phototransistor is Kingbright KPA-3010P3C.
  14. R

    Phototransistor

    Hi, I am testing the circuit below. My understanding is that light controls the current from the base to emitter, which controls the collector current. I am powering from 3V. I see a change of 0.2V (when it is dark)to around 2.8V at the output (light conditions). I am trying to understand the...
  15. R

    Pickit3 or icd3 programmers

    Thanks for the reply. I will have another good read through the Microchip da. tasheets.
  16. R

    Pickit3 or icd3 programmers

    Hi all, Is there anyway to make the PICKit3 or ICD3 as gang programmers? Mostly programming PIC18F family under MPLAB. Is there any information available to understand the process of prigrammung i.e. VPP, Clock and data signals etc. Thanks in advance.
  17. R

    Wanted: Student Manual Art of Electronics

    Hi all, I am after a book: Student Manual - Art of Electronics I have seen it on Scribd. But does anyone have a copy of this that they want to sell or a PDF copy? Thanks.
  18. R

    A/D impedance PIC connected to RC circuit

    Hi, sorry but i cant seem to.upload files. Keep getting errors. I will upload tonight from my PC. Thanks
  19. R

    A/D impedance PIC connected to RC circuit

    Hi all, I have a RC circuit in parallel 330K and 1uF. This is going to be connected to an A/D input of a PIC. The PIC is a 16LF1936, which says the impedance is 10K source. 1. How do i calculate the impedance of the RC circuit? I think it is Z=squareroot of RxR + Xc x XC. XC is the reactance...
  20. R

    Wavelength and matching components.

    Hi all, I was trying to find the difference of wavelength of 868MHz compared to 928MHz. Using a online calculator i found that the wavelength if 868MHz is 34.5cm and 928MHz is 33cm. If i wanted to use a printed antenna, would i simply make the length of the track 33cm? What hapoens to matching...
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