Where is the resistance coming from?

Hi.

I designed and built this circuit: https://www.circuitlab.com/circuit/ebrb94/avr-master/

When this circuit has no power supplied, between +5V and GND I measure 4860 ohms resistance. When I attach a 9V battery and turn the circuit on, the resistance between +5V and GND is unmeasurably high. Where does that resistance come from when there is no power? I'm measuring with a DMM on a real circuit. I've checked for solder bridges etc.

Richard

You can't measure resistance when the unit is powered up, and you're likely to damage your meter attempting to do so.

The resistance is simply via the components in the circuit, but isn't really something there's any reason to be checking anyway?.

Ohmmeters apply a current or voltage to the circuit to measure the resistance. If you power the circuit, the circuit voltages will give you erroneous readings or even damage the meter.

Your schematic is small on a huge webpage. It has no contrast. Its details cannot be seen.
I doubled its size and added contrast but its details still cannot be seen.

Try this one, audioguru.