If an averaging amplifier has 5 inputs, the ratio Rf/Ri must be:a.0.2b.0.1c.5d.2

An averaging amplifier is a type of operational amplifier where the output voltage is the average of the input voltages. It is used to reduce noise and improve signal quality. The ratio Rf/Ri in an averaging amplifier is determined by the number of inputs.

Here's how you calculate it:

Step 1: Understand the formula. The output voltage (Vout) of an averaging amplifier is given by the formula Vout = -(Rf/Ri) * (V1 + V2 + ... + Vn)/n, where n is the number of inputs, V1, V2, ..., Vn are the input voltages, Rf is the feedback resistance, and Ri is the input resistance.

Step 2: In this case, we have 5 inputs (n = 5). We want to find the ratio Rf/Ri that will give us an average of the input voltages.

Step 3: To get an average, the sum of the input voltages should be divided by the number of inputs. This means that the ratio Rf/Ri should be equal to 1/n.

Step 4: Substitute n = 5 into the formula. We get Rf/Ri = 1/5 = 0.2.

So, the correct answer is a. 0.2.