I am using my Arduino uno to generate a 500Hz Square wave between 0 and 5 volts. I am measuring the signal from the Arduino using an oscilloscope and instead of measuring 5 volts peak to peak, it measures 500 millivolts. I have checked everything and cannot find anywhere a mistake. Why is this happening ?
Make sure your scope and scope probe scaling are set to the same setting. If your scope probe is set to 10x, make sure your scope is set to 10x.