SIGNAL AMPLIFIER
In addition to the capacity amplifier, pneumatic systems also use a signal amplifier. Generally, modern amplifiers use diaphragms for control logic instead of levers, bellows, and linkages.
A signal amplifier increases the level of the input signal and provides increased flow. This amplifier is used primarily in sensor-controller systems where a small signal change from a sensor must be amplified to provide a proportional branchline pressure. The signal amplifier must be very sensitive and accurate, because the input signal from the sensor may change as little as 0.06 psi per degree Fahrenheit.
Another use for a signal amplifier is to multiply a signal by two to four times so a signal from one controller can operate several actuators in sequence.