draw a diagram of current use.

[lgrfbs]

Hi
I want to draw a diagram on the win PC of current use for a part I are testing how do you do it?
I want to see if the part (turnout servo) do a spike draw of current and how it use the current.

[tyblu]

You have to either connect a multimeter in series with the servo and switch it to current measurement mode or put a small value resistor in series with the servo and measure the voltage drop across it (I = V/R). If you want to capture a quick spike and don't have an oscilloscope, you can still place a small value resistor in series with the load, estimate the maximum current value which gives you a maximum voltage drop across the resistor, then divide that voltage down to logic level (~5V) using a voltage divider (2 more resistors), and input it into a latch, a device that 'remembers' if its input has been a logical '1' (5V for TTL). If you're not sure what the maximum current value is, estimate something out of range and construct your 5V divider from that amount, then work your way down in divisor values until the latch 'latches' (the voltage across divider reaches ~5V). If the event is more than 25ms long (1/40Hz) you should be able to see it with your eyes, and can use an LED, but this can be tricky.

[lgrfbs]

tyblu I have a Telequipment oscilloscope D61, I think it is a 10M scope.
Will try as you writes me.

[tyblu]

Alright, then you can just put a small resistor in series with the load and measure voltage drop across it with your oscilloscope. If you expect a large current draw use an appropriately sized resistor or combination thereof (P = R*I^2). A resistor at least 1/10th the resistance of the load should be small enough not to change your measurement by much.