I and trying to create a Unity Gain Differential Amplifier using LM324 opamp. Circuit diagram as below, In this all resistance are of 10k values. Theoretically output should be difference of both the inputs but somehow the result are totally different.
Supply voltage: 5V
Input voltage: 3.24V
Output voltage 1.1V and decreasing if keep connecting voltmeter.
Mind that the "input voltage" with this difference amplifier is defined as: V_in = V2 - V1
In any case you have to take care that the Opamp input voltages are within specified range.
And mind that the output voltage will never reach the supply voltage rails...there will always be some dropout voltage.