Higher precision amplifier circuit
The following figure shows an inverting amplifier circuit and a non-inverting amplifier circuit using an operational amplifier. The amplifier gain is determined by the ratio of R1 to R2. To achieve the required gain without any adjustment, resistors for R1 and R2 must have small resistance tolerance and T.C.R. Accordingly, Metal film type resistors RN73R, RN73H
and High Reliability Chip Resistors, RS73 series, are suitable.
Network resistors, chip resistors incorporating paired resistors, work in this application as well. Building two resistors concurrently achieves excellent relative accuracy and T.C.R. In fact, KOA‘s network resistor, CNN2A
, has two embedded resistors with the individual T.C.R. of ±25ｘ10-6
/K, which is 5ｘ10-6
/K or less in relative. In addition, KPC
series has two or more resistors in one package, which enables better relative precision and high density mounting.