Recent content by HellasTechn

  1. HellasTechn

    Trying to identify a resistor network

    Yes i agree, but maybe the damage took out all internal wiring ?
  2. HellasTechn

    Optocoupler & mcu

    Okay, got it. In my case im thinking to use some opto with low forward bias current led so that i will not need a diode of large wattage. The circuit of the above post is interesting indeed though i think that the zener could be skipped by increasing the value of r3 and replacing C2 with a 4.7uf...
  3. HellasTechn

    Optocoupler & mcu

    Actually the IR led's forward voltage is not mentioned. Only the reverse voltage. The datasheet only states the forward current which is 60ma for the ET1103 so i suppose any reasonable voltage on the LED with a suitable series resistor to limit the current to no more than 60ma should be okay.
  4. HellasTechn

    Optocoupler & mcu

    Do you think that a et1103 would be suitable with a 150K resistor in the anode of the IR led ?
  5. HellasTechn

    Optocoupler & mcu

    Yes you are both correct. Looks like polarities are messed up and the cap is no good placed like that. So the diagram i found online is wrong. Could you suggest me some optocoupler and resistor value for it's Anode pin ?
  6. HellasTechn

    Optocoupler & mcu

    Hello everyone ! My latest project involves a micro controller and a solenoid that works with 220VAC. Once the solenoid gets the 220VAC on its coil, it opens for a few seconds. My goal is to count how many times the solenoid opens. I Think that i can use a bridge rectifier and an optocoupler to...
  7. HellasTechn

    Opamp test circuit.

    Here is the corrected diagram and a comment. At the cathode of D3, which is actually the inverting input of the opamp, the waveform should be exactly same as at it's anode since there should be no current flowing through it due to the very high impedance of the opamp's inputs. A potentially...
  8. HellasTechn

    Opamp test circuit.

    I noticed one more mistake in my above circuit. The smoothing capacitors must be placed at the other end of each rectifier diode...
  9. HellasTechn

    Opamp test circuit.

    Yes it's been a while since my last visit. Im into alot... Do you have something in mind ?
  10. HellasTechn

    Opamp test circuit.

    Or passing Vi through a diode to use it's forward bias voltage drop.
  11. HellasTechn

    Opamp test circuit.

    Hello everyone. today i was thinking of a test circuit for opamps like the 741. i made a diagram. What do you think of it ? Thanks !
  12. HellasTechn

    7486 IC problem

    As mentioned above, the 74 serries IC's can only sink or source a few mA of current. Also 9V is too much. It might withstand a few "shots" of it but definitely not continuous supply. if you supply it with 5V then you can use an npn transistor like the BC337 connected to the output to run the...
  13. HellasTechn

    Diving into JTAG

    Thanks !
  14. HellasTechn

    Diving into JTAG

    Guten tag Harald, i want to get to know both jtag in general and the specific tools if possible. I mean if someone knows how to put those tools in practical use, i would appreciate the assistance. I have those at work and i do want to learn how to use them. Further more if someone can suggest...
  15. HellasTechn

    Diving into JTAG

    Hello everyone, the past few days i got my hands on two very nice tools that i would like to get to learn how to use. 1st is an ABI JTAG master and the 2nd is a JTAGULATOR board. There are videos on youtube about JTAG and JTAGULATOR but since i have never used tools like these before and it's my...
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