Recent content by jgauthier

  1. jgauthier

    NOR flash programming

    This seems very specific to the Versatile/AB926EJ-S Single on board computer. But i could implement a physical switch like they are talking about. I'm just quite limited on space.
  2. jgauthier

    NOR flash programming

    I am going to implement a microcontroller based on ARM926 that boots from a NOR flash chip. I also want to program that NOR flash chip on board (non-removable). The programmer will power the chip, but while the rest of the circuit is off, I do not want to have the programmer power the rest of...
  3. jgauthier

    Op-Amp voltage follower output different from input

    Unfortunately, utilizing the last channel did not change the result. I connected my 1.65V input to the unused channel, and the output is also 1.8V. I can however, easily input 0V to that channel to test it. But I have to put it down for now. Thanks for the help.
  4. jgauthier

    Op-Amp voltage follower output different from input

    I removed all the other inputs, and put the 1.65V back into pin 3. 1.8V comes out. Still. I checked the datasheet and it agrees with you: "Any unused channel of the ADA4522-1/ADA4522-2/ADA4522-4 must be configured in unity gain with the input common-mode voltage tied to the midpoint of the...
  5. jgauthier

    Using AC/AC wall adapter and converting to DC

    I could pull off D5 and D6 and connect them through wires. It would not be too enjoyable. :)
  6. jgauthier

    Op-Amp voltage follower output different from input

    Hm. Well, I removed R22 and R23, for the voltage divider input. I verified on the schematic that was not used anywhere else. But, the input showed 1.7V and the output now showed 3.9V. Pictured here, pins 1,2,3 are the ones I brought up in the initial post. Pin 5 is 1.65VAC that is obtained...
  7. jgauthier

    Op-Amp voltage follower output different from input

    I am using this op-amp. I have a positive rail (about 10V) and a negative rail (about -13V) explained it in this other post. The op-amp is basically being used a voltage buffer. In my application I have 10 ADC inputs reading current transducers. I am offsetting the current transducer by...
  8. jgauthier

    Using AC/AC wall adapter and converting to DC

    I have a "12VAC" wall adapter. The RMS voltage is really about 9.8V. It's rated at 1000mA. I have a small rectifying circuit to get DC +/- voltage for an op-amp. The negative side of the DC voltage is -13V. The positive side is about 10V. The downstreamdevice seems to pull about 630mA (at...
  9. jgauthier

    Some input/help on this circuit

    @Harald Kapp Thank you for the your detailed response. I learned about the "dual supply" trick after posting. But that page, and the virtual ground page were both excellent. I am going to explore both options.
  10. jgauthier

    Some input/help on this circuit

    Design goals: I have a 9VAC (1A) power supply. I want to power some microprocessor boards with this, as well as monitor it's signal. (the whole scope is larger, but this portion is isolated to the power supply and interactions with it) My plan is to rectify the 9VAC into DC (then use DC/DC...
  11. jgauthier

    Common mode choke - short?

    Thanks! I just discovered that to be the case!
  12. jgauthier

    Common mode choke - short?

    Hello, I am experiencing weird behavior with a common mode choke and had a few questions. The circuit in question is this: I am using a desktop power supply at 28V and 200mA current. This is the first time I've powered this board. Immediately, the voltage dropped to 0.64, the current went to...
  13. jgauthier

    Help with shunt resistor

    This is most likely an Ohm's law question, but I feel like I need a little help with it. I have this circuit that I use on a low voltage low current system in order to measure the current. My device load is 5V around 3A (peak, not sustained). I'm just looking for some advice on the...
  14. jgauthier

    Multiple GPIOs to direct different voltage to a single device

    Thank you for the clarification. I should have included a schematic versus a block diagram. My idea was similar to this one, except for the relays. This makes more sense.
  15. jgauthier

    Multiple GPIOs to direct different voltage to a single device

    Sorry, I don't understand how those would work. The two triggers are independent. They will switch the 9V and 3V signals (that isn't really shows) The issue I am trying to solve is getting those 9V and 3V signals on the same line as an input to the device (separately) while also protecting...
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