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  1. (*steve*)

    Triac replacement

    Actually the body diode in the MOSFET will make it conduct in the reverse direction. The impedance of the gate of a MOSFET is much higher than the gate of a TRIAC, so it's possible that you'd exceed Vgs(max) and destroy the gate. It would be hard to predict what happens next. When all you...
  2. (*steve*)

    Triac replacement

    Sure, but the dimmer won't work any more and the failure mode might be interesting.
  3. (*steve*)

    High Low logic

    The voltage between the adj and output pin is held constant with a very low current flowing through the adj pin. This the current through the resistor between the output and ground is constant allowing the output voltage to be easily changed by altering the resistor between adj and gnd. So...
  4. (*steve*)

    What sensor can be used to my IOT device?

    The carotid artery is in your neck. You probably mean the radial artery.
  5. (*steve*)

    P=I*R

    Well, if they know the current and the resistance, it's the logical choice. P = V²/R and V = √(PR) are also useful in many cases.
  6. (*steve*)

    DC currents through Rd and Rs in JFET amplifier

    That biasing is fine. Assuming values are chosen appropriately, the source voltage will rise until Vgs is an appropriate negative voltage (source more positive than gate) at the operating point. Given that all these devices are voltage controlled current sources, it's not surprising you can...
  7. (*steve*)

    Accuracy of digital multi-meters?

    The Wikipedia entry on resistor ladders is pretty good. The penultimate section talks about the resistor accuracy required to retain monotonicity in the output (i.e. that the output always goes up as the binary value increases). The next constraint would be that the step is within 1/2 the LSB...
  8. (*steve*)

    Accuracy of digital multi-meters?

    I've only briefly looked at your correct, but you seem to have a 6 bit DÀC made from discrete resistors. R2R networks are very dependent on tolerance, but also that the ratios are accurate. If you matched the 200k resistors, did you use 2 of these in parallel for the 100k resistors? Also, you...
  9. (*steve*)

    ETI magazine Feb 1979 - power supply (ETI-142)

    On the unit I have, there are a couple of resistors bodged onto one of the boards. I expected them to be emitter resistors, but they are in the collectors of the 2N2055's. This is a little confusing, and I didn't manage to find errata for this project so I'm not sure why they're there. On...
  10. (*steve*)

    ETI magazine Feb 1979 - power supply (ETI-142)

    My local reference library has copies of the February 1979 ETI (the Australian version), and I have photographed the article. I might try to clean them up a bit more later, but here they are, hot off the phone (almost)... There's some interesting design techniques here: Input...
  11. (*steve*)

    Pins with pullup resistors built in

    In the PIC environment, making a pin an analog input disables the input buffer, so the setting of a weak pull-up is mooted. However, it appears that atmel don't follow the same strategy because there is a warning that setting weak pull-up on a pin set for analog input will affect the values...
  12. (*steve*)

    Battery Powered Variable Power Supply

    Depends what you're using them for.
  13. (*steve*)

    Newark / Farnell / Element 14 become my new "supplier of last resort"

    The incompetence never ends... I just called up the Australian office of Element 14 to complain. I asked them to cancel my US order, but to leave my (5 week lead time) Australian order. What did they do? They deleted my Australian order and left the US order. So I've called them again...
  14. (*steve*)

    Newark / Farnell / Element 14 become my new "supplier of last resort"

    I'm looking for a Keithley 6172 triax adapter. It's not common, probably due to the fact that it has always been a specialty part, and never in great demand. Most of the larger suppliers have them listed as out of stock or obsolete, but I found them listed on Element14's web site with an...
  15. (*steve*)

    Connector Recommendations

    Look at the connectors used in model aircraft (and other models) used to connect to LIPO batteries. Another option are the Anderson connectors which are occasionally seen on UPS's for the connection of external batteries. I believe there are bulkhead adapters for these.
  16. (*steve*)

    Leds under rain

    I don't really understand the question about what would be worse. However, I would suggest that you should look at a conformal coating and/or potting your devices.
  17. (*steve*)

    Capacitor

    I would use a 1.8uF and a 0uF capacitor, or just a 1.8uF capacitor. Is this homework?
  18. (*steve*)

    Need advice on issues with a 40pin 0.5mm pitch FPC cable and its adapter

    Do you have a socket for that cable that you can solder to the adapter board?
  19. (*steve*)

    PwM using microcontroller

    Convert the pwm input to a voltage, read that voltage and use it to control the output pwm. How fast you want the circuit t respond.
  20. (*steve*)

    Disable backlight of LCD monitor

    You might be able to get away with replacing the backlight with a resistor that will draw approximately the same power as the backlight. Is it a CCFL or a LED backlight?
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