larryd:
What range of resistance do you expect ( .1/1/10/100 etc. ohms ) ?
10 to 70 ohms.
Basically im working on a project that measures resistance between 2 earth cables. So I want use and external psu to inject 24VDC into the earth cable and then measure the resistance. There will be a dip switch to preset the resistance value. For example, If dip switch 1 is on..then preset is 10 Ohms. If the measured resistance is more than the preset, then an sms will be sent to user notifying that earth resistance is high. However, if measured resistance is lower than dip switch preset, then sms will be sent saying everything is OK.