Difference between Strain Amplifier and Signal Conditioner
Amplifiers for measurement of dynamic variables are available in 2 types: AC bridge excitation and DC bridge excitation. In Kyowa, amplifiers using AC bridge excitation is called Strain Amplifiers and amplifiers using DC bridge excitation, Signal Conditioners.
Since the strain amplifiers have the bridge circuit affected by capacitive components, both resistive and capacitive components should be balanced at the initial adjustment. In addition, the AC frequency of the bridge voltage limits the frequency response to lower than the DC system. But the AC bridge voltage system provides higher sensitivity and is highly resistant against external noise, thereby making strain amplifiers excellent in SN ratio and zero stability and free from thermoelectromotive force. Thus, strain amplifiers are most frequently used for strain measurement with strain gages. Furthermore, current strain amplifiers adopt the CST method, which automatically balances capacitive components and requires no adjustment by the operator for improved operational efficiency.
The signal conditioners using DC bridge excitation requires balance of resistive components only at the initial adjustment and provide higher frequency response but SN ratio and stability are inferior to the strain amplifiers. But the DC bridge voltage system provides higher output voltage than the AC bridge voltage system, and thus signal conditioners are frequently used for measurement with strain gage transducers.