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  1. chopnhack

    PCB Repair gone wrong

    Welcome Sotiri! Are you able to borrow a multimeter from someone and check the diodes for correct operation? There should be open resistance in one direction with little resistance in the other direction. That way you can check D1 to make certain that what you are seeing is indeed a crack in the...
  2. chopnhack

    Electronics Point:1 Chat Room Open!

    How's the project going CJ? I first liked the idea, then I saw that it was through FB :rolleyes: Have you had much activity?
  3. chopnhack

    GPS NMEA, Failover Circuit upgrade attempt.

    When you say the supply line, do you mean that the ripple occurs at pin 16 of the chip or you see ripple on your bench power supply after connecting it? Repeat with your supply at same setting of 5v and a simple load resistor like a flashlight bulb and see if the noise is still there. That can...
  4. chopnhack

    GPS NMEA, Failover Circuit upgrade attempt.

    I guess to be on the safe side, measure according to the datasheet for your particular chip and see if the resistors are inline with the pin. If not, add them and test out the circuit. I am glad they came! And we just talked about them, LOL. If they fail, go to the link I sent you onGPS NMEA...
  5. chopnhack

    Voltage Drop across NPN BJT C&E?

    No, it is an S9018 that I received from a Chinese E-bay seller as part of a sample of various transistors, so I don't believe its necessarily a Fairchild SS9018 as I linked, but it seemed to have similar characteristics as the Fairchild model. That datasheet was not only in English, but seemed...
  6. chopnhack

    Voltage Drop across NPN BJT C&E?

    Hop, I will repeat with 5v and appropriate resistor to get 10mA and see what I get, hopefully tonight. If the fet version is doable I will order a sample of bss108 or bsh135's. I thought that in circuit they are less vulnerable, but hadn't researched it.
  7. chopnhack

    Voltage Drop across NPN BJT C&E?

    Scrapping the MOSFET idea due to static sensitivity, I would like to use a N channel BJT to turn on/off a circuit. The base will be taken high by a pic output. With some testing tonight using a S9018 transistor, I found that by biasing the base with various resistances, I was able to get...
  8. chopnhack

    Help with N-Channel Mosfet as a switch at low voltages.

    Good point TedA! I didn't think of that :mad::( I figured for a battery powered, small device, static wouldn't be an issue :oops: I have some transistors, I will pick through them and see if any will meet the requirements for the circuit. BJT's annoy me, I never seem to have luck properly...
  9. chopnhack

    Help with N-Channel Mosfet as a switch at low voltages.

    Thanks Bob, how are you deriving 300mA for that particular voltage? I am still very leery of reading/interpreting transistor data sheets!
  10. chopnhack

    Help with N-Channel Mosfet as a switch at low voltages.

    I need the fet to function down to about 2.2V and it would only need to supply a limited amount of current (less than 1ma), would this be a good option? http://www.nxp.com/documents/data_sheet/BSH105.pdf
  11. chopnhack

    Help with N-Channel Mosfet as a switch at low voltages.

    Thanks Bob, I thought I was good with VGS(th) of 2.1, but as you mention, that was at a different voltage level and may not scale down. Thanks for the help, off to digikey to look for a solution.
  12. chopnhack

    Help with N-Channel Mosfet as a switch at low voltages.

    Hi Bob, I neglected to mention that R1 is 1MΩ and that there was a load between Vcc and Q1's drain - I left it out for clarity because when I had the LED in, the circuit did indeed function, but when I tried to use the assembly to switch another load, I was not getting the 3V I needed to the...
  13. chopnhack

    Help with N-Channel Mosfet as a switch at low voltages.

    Hello all, I am working with a 2n7000 N-channel MOSFET and not getting the desired effect. I was expecting to use the fet to switch power to the rest of my circuit at 3VDC. I checked the data sheet and it says that my typical VGS(th) is 2.1 so at 3VDC I should be able to saturate the gate...
  14. chopnhack

    What is special about solderable enamelled copper wire?

    Sean, the purpose of this is to make repairs easier. Lets say you need to make a repair in a motor winding with limited area to work in, you can simply heat the wire with your iron and the enamel coating will melt away in the flux.
  15. chopnhack

    Does anyone know the name of this connector

    I have had luck with calling TE before and talking with their connection specialists. They can narrow down comparable connectors. +1 800 522 6752
  16. chopnhack

    Does anyone know the name of this connector

    No, the PS2 connectors don't have angled slots for the pins to go into like the OP's picture. They are just round holes and are arranged in a rectilinear format. freeshell.de
  17. chopnhack

    GPS NMEA, Failover Circuit upgrade attempt.

    Hi Constantine, I had some more time to look for a vendor that delivers to Greece - aside from RS that handles transactions for small fees, Tayda Electronics comes to mind. They are a major outfit and I have ordered from them several times. The quality seems good. I looked on the net for some...
  18. chopnhack

    GPS NMEA, Failover Circuit upgrade attempt.

    Oy! :eek: Constantine, I use ebay too, but this is a critical piece of your hardware, please consider getting from a reputable source so that you are not chasing your tail. Digikey has free shipping to Greece on $100 order or more, I am sure you can do better with European outfits, have a look...
  19. chopnhack

    Designing a Time Delayed Relay

    I have a Hakko FX888d that I enjoy using very much - it's temperature controlled, even so I had it up at 800 degrees to do this operation. I felt confident enough to do it because I didn't spend anywhere near as much time as the video demonstrated and the board is 2 oz. That would certainly be...
  20. chopnhack

    Designing a Time Delayed Relay

    That would be interesting, but I went high tech red neck and got'er done. :D I saw two videos on desoldering smd's - the first was very interesting in its use of magnet wire to slide under each pin, I had no luck with that method since of the tall connectors nearby preventing getting a good...
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