Voltage Trigger Problem - High Voltage to Low Voltage

- B
- beginner1.mat
  
  Contact options for registered users
posted
8 years ago

Fri, Feb 5, 2016 1:05 AM

I have connected a switch (off/on) to a USB output on my computer. I measure 5V from the end of the USB that is going to my switch. I am recording the voltage going from high (5V) to low (0V) when the switch is turned off/on. My problem:

The voltage I record does not drop off fast, it drops off fast to about 1V, then slowly to 0V after 10 seconds or so.

I tried a different USB outlet on a different computer (laptop) and it seems to work better most of the time (drops fast to 0V).

Any reasons why I would see the "slow" drop using one vs. the other? Any thoughts on troubleshooting would be appreciated.

- M
- M Philbrook
  
  Contact options for registered users
Vote on answer
posted
8 years ago

Fri, Feb 5, 2016 2:57 AM

WHat ever load you have connected to the LOAD side of the switch is loading the output down until it reaches a diode volt or two.

The load could even be your meter, I've seen some really cheap ones.

Jamie

- R
- Robert Baer
  
  Contact options for registered users
Vote on answer
posted
8 years ago

Fri, Feb 5, 2016 6:14 AM

Terminate..

- M
- mike
  
  Contact options for registered users
Vote on answer
posted
8 years ago

Fri, Feb 5, 2016 8:52 AM

Are you measuring the voltage unloaded? Put a load on it and measure again.

If loaded, what's going on inside the load?

I once built a GPIB interface that hooked the outputs of a PIC processor to the bus. I turned off the power supply and the damn thing kept working. I was gonna post my results in the free energy groups and start a crowd funding campaign to continue development. But, alas, it was the voltage on the bus feeding back thru the output and running the processor. Bummer.