Recent content by Sunnysky

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  1. Sunnysky

    ECU repair

    As long as the output has large Vac, the 1Meg DMM may stop the clock when probing the input pin, it is ok when released. Avoid ESD with a finger on the case.
  2. Sunnysky

    ECU repair

    - with power, the CPU crystal has 2 pins input and output. When measuring on DC both should be roughly half of the chip V+ to ground. On Vac the output should be a full scale square wave , will be x Volts. and not near 0 mV. This is essential. You can inspect the solder for a hairline...
  3. Sunnysky

    Losses in LTSpice

    errors still exist in log after edits ERROR: Node u1:x1:x_rs:m is floating and connected to current source u1:x1:x_rs:G1 ERROR: Node u1:x1:x_rd:m is floating and connected to current source u1:x1:x_rd:G1 ERROR: Node u2:x1:x_rs:m is floating and connected to current source u2:x1:x_rs:G1 ERROR...
  4. Sunnysky

    Small circuit design

    The most efficient solution is to choose a current-limiting resistor that drops X<< 1 V. The R will dissipate 350 mW at 1V, and you should select a power rating at least twice to reduce the temp. rise from 120 to 60 °C above ambient. This demands you choose a power supply that is N* Vled + X...
  5. Sunnysky

    The official Xmas/holiday thread 2025

    https://youtu.be/aH54-DpHeB0?t=1361 New Year's swarm drone show in Yerevan town square. We were there in October when they just had nightly musical colourized dancing waterworks. They do have a company that can control drones for some purposes, and are planning a new drone factory, but this is...
  6. Sunnysky

    If You're an Engineer

    If one takes the time to recognize the pattern on the shell, that will improve your odds but takes just as long. But the odds ought to be 50% unless you forget about precognition bias.
  7. Sunnysky

    Battery treatment

    A cutoff below 20% accelerates the reduction in life recharge cycles rapidly. Short-term gain vs long-term pain. That's why it is shaded in red.
  8. Sunnysky

    The official Xmas/holiday thread 2025

    Greetings with the seasons. May you enjoy the spice of life. I lost the belly this year but my wife says I have no bum left too.
  9. Sunnysky

    Small circuit design

    Here's a method using a Festoon car lamp that is close to the resistance <1 Ohm cold. Reverse protection diode added (opt) Disable can be made active Low with a simple change. Simulation < press continue to destination = Falstad Interactive sliders for Vbat and Lamp Power rating at 14.2...
  10. Sunnysky

    3v step down from 12v

    TL;DR Why bother when you can put 4x 3VLEDs in series and repeat as many in parallel as you want and switch on/off from ground with an NPN. If that isn't enough current or your 12V reg is worse than 2% use 3 in series with a R to drop slightly less than 3V for I=V/R Or do you need 5V for...
  11. Sunnysky

    Best approach to sweep 410-525 MHz? PLL/VCO vs ramped timer vs sweep-IC?

    Best for what? resolution? Phase noise ? cost? Analog Devices ADF4355 or Texas Instruments LMX2594. e.g. https://www.analog.com/media/en/technical-documentation/user-guides/EV-ADF4355SD1Z_UG-805.pdf https://www.ti.com/product/LMX2594#tech-docs https://www.ti.com/lit/an/sbaa653a/sbaa653a.pdf
  12. Sunnysky

    Anyone Using NEMA 23 Stepper Motors in Robotic Applications?

    Can you define anything for load force vs desired velocity then no load max acceleration with max mass? max position error per step? You can use any 8mm belt pulleys to trade off speed and resolution for torque but don't under spec it and consider making vibration & noise specs. MRI scanners...
  13. Sunnysky

    Anyone Using NEMA 23 Stepper Motors in Robotic Applications?

    Servo motors vs steppers of same size will limit your torque but reduce the noise. Go with larger NEMA 34 motors and higher V+ with 3A drivers for enough power. The motors may need miniature fans. If you need torque to mill aluminum, you will need much more torque using full steps which causes...
  14. Sunnysky

    Small circuit design

    A safer , simpler method , if you "must" use 12V is to waste the heat in a 5W 15~20 Ω series R depending on the Vf at 350 mA The beauty of Falstad is you can model any diode with a simple or complex model using the datasheet min/nom or max Vf values @ If. . The safe limiting factors are...
  15. Sunnysky

    Small circuit design

    This LED power is not well suited to the LM317 and will not work at 9V. It needs at least 10V and 12V is too hot or inefficient. Here's how to model it in Falstad Analog cct design. Add LED under Draw> Outputs ... then edit it following the datasheet.. Add LM317 per below arrows. I changed...
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