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  1. dorke

    Signal generator using 555 timer

    Nice start, I wonder what scope have you ordered? Are you aware of Software Audio Scopes and signal generators that are free on Pcs and Smart phones?
  2. dorke

    USB to UART serial converter.

    Chris, This thread has become a spaghetti bowl... I didn't go through each and every post. If what you are describing is indeed the case then there is no problem. But still, One has to ask about the distance between the PC and the uC board. For a very short distance say 1meter or so ,it will...
  3. dorke

    USB to UART serial converter.

    Not so simple, The TTL input will be smoked by the levels of the RS-232 voltages especially the negative voltage. A double clamp should be implemented to +VCC and GND to prevent that destruction.
  4. dorke

    current limiter for dual rail power supply.

    Of course they will smoke! they are way to small for the job!!! The load may be 12V @1.5A for each voltage ,that is twice 18W=36W. Each regulator will dissipate about (1.4*12-12)*1.5= 7.2W, that is 14.4W The total is about 50Watt of power. To be on the safe side ,use a 60Watt transformer...
  5. dorke

    current limiter for dual rail power supply.

    What kind of wall-wart are you using ? Have a picture or specs? Voltage/current/power . The manufacture is correct the LMXX Ics have both thermal and short circuit protection. Is the Wall-wart the only thing that smoked?
  6. dorke

    USB to UART serial converter.

    Oh, He absolutely has the sand alone chip,that is what's on the module( #69). It connects directly to USB and produces CMOS(TTL compatible) interface to the "rs-232 side". From #73 you can confirm that the levels are 0-3.5v. That isn't RS-232 compatible thus a rs-232 transceiver is absolutely...
  7. dorke

    USB to UART serial converter.

    Very important !!! The CP2102 is not an rs232 compatible device,you have to add a rs-232 transceiver!!! connecting it directly to a RS232 port will destroy the IC(in case the output of that port is larger than 5.8V,or smaller than -0.3v, which it will be!). The device output of 3.5V at idle is...
  8. dorke

    USB to UART serial converter.

    Not enough info. But lets see, they are using the CP2102. The UART side is for connecting to a Modem(DCE equipment). Therefor the way you use it depends on what kind of equipment you connect it to : 1. If to DCE(like modem) connect directly,and connect DTR to DTR as well. 2. If to DTE(like PC)...
  9. dorke

    High Low logic

    Actually with t this kind of regulator (LDO) the output at the Adj.pin is related to Gnd ,not to the output. see #10 and #16 above. Is using this voltage for other purposes possible? Yes, if you don't load it. i.e (connect it to a high resistance "input",or use a high resistance buffer). This...
  10. dorke

    High Low logic

    Bob, we are saying the same thing. The voltage on the Adj. pin will be equal to Vref=1.22v while in regulation mode. That means that the op. amp.(error amp.) isn't saturated,and the negative feedback loop is closed(active). i.e V(+)=V(-)=Vref at the inputs of the op.amp.
  11. dorke

    Garage Door opener capacitor replacement

    If it plugs to 120V outlet,and it worked before the fault ,it is a 120V motor. In this case you can go along with the lower capacitor voltage. The operating voltage of a motor should be written on it.
  12. dorke

    Need help on circuit.

    What is the relay coil current? Try this:
  13. dorke

    Omron

    It is a 12VDC automotive relay,looks melted, OMRON part number G8ND-2. You can get it from Ebay for 8$ may be a fake. You should also try digikey and mouser(higher prices,but no fakes guaranteed)
  14. dorke

    I Want To Make A Device That Tells Me That Electricity Is Back

    :):):)
  15. dorke

    High Low logic

    That is correct. That is why I suggested using the reference voltage of the LT1763. There are compactors with internal voltage reference, like the TLV3011-2 , that can be used. But in general, What you really need is a battery charger IC with integrated PowerPath control.
  16. dorke

    Need help, 12v water pump - wire a wall adapter ? Bare wires.

    Yes, it will work. There is no info of the adapter's DC plug size on amazon. You will need to measure it when it arrives(inner an outer diameters), only then buy the terminal adapter.
  17. dorke

    Need help, 12v water pump - wire a wall adapter ? Bare wires.

    Well, A typical Chinese cheaply. Yes it is DC,red most probably the (+) terminal. Get a Wall-Wart of 12VDC (un-regulated should be fine). It should be at least 3A ,so better go for higher,say 4A. One way to connect is shown below:
  18. dorke

    High Low logic

    Well, It is an input ,no doubt. It will be fixed at Vref. ,as long as there is a closed feedback loop. i.e the op. amp in the diagram isn't saturated.
  19. dorke

    High Low logic

    Well not in this case! The Adj. pin voltage of the LT1763 is referenced to ground not to the output! It is a fixed voltage at 1.22v ,the band gap internal voltage reference(that is why I said it is easy to use)! It is clearly stated in several places in the data sheet. Note also that the output...
  20. dorke

    Need help, 12v water pump - wire a wall adapter ? Bare wires.

    Welcome to EP. A photo and datasheet will help us help you. Is it a DC pump?
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