operational amplifier (thing)

The symbol below represents an op amp. The top input is the inverting input V_I, the bottom is the non-inverting input V_NI. The two vertical lines marked V_CC and -V_CC are the op amp's power supply, and are usually connected to the positive and negative power rails (voltages range from around 4-15V), although a couple of circuits (eg the integrator) have the power supply connected to positive and zero voltage rails. V_CC is an abbreviation for 'supply voltage'.

   
             VCC
        |\   |
        |  \ |
VI -----|-   \
        |      >--- VO
VNI-----|+   /
        |  / |
        |/   |
            -VCC

There are many different configurations of op amp. Here are a few configurations that may come in useful.

• Inverting amplifier
• Non-inverting amplifier
• Voltage follower
• Comparator
• Difference amplifier
• Summing amplifier
• Integrating amplifier