What is the difference between preamplifier and power amplifier?

Preamplifier refers to the circuit or electronic equipment placed between the source and the amplifier stage , It is specially designed to receive weak voltage signals from the source . It can convert weak current signal into output signal, which is strong enough , The signal with strong enough noise tolerance can be used for further processing , Avoid signal distortion .

（ Circuit diagram of a weak signal preamplifier ）

The preamplifier amplifies the noise while amplifying the useful signal , Low noise preamplifier is a preamplifier that minimizes the noise figure of the circuit . For weak signal detection instruments or equipment , Preamplifier is one of the main components to introduce noise .

（ A preamplifier circuit ）

The noise figure of the whole detection system mainly depends on the noise figure of the preamplifier . The minimum signal that the instrument can detect also depends mainly on the noise of the preamplifier .

Why are there so many kinds of preamplifiers on the market ？

Because for different kinds of measurements , The specific requirements are also different . When amplifying the sensor signal , It is often necessary to choose the appropriate preamplifier according to the type of Sensor .

The temperature sensor is generally voltage output , Therefore, voltage input preamplifier should be selected . Photodiodes used for optical detection are generally current output , Therefore, the current input preamplifier should be selected .

The difference between preamplifier and power amplifier

Simply speaking , The preamplifier is the millivolt (mV)、 Microvolt (V)、 nanovolt (nV) Stage small signal amplification To millivolts , Volt level . It can be detected on the oscilloscope and other testing instruments , No output power to drive the load .

The power amplifier is the millivolt of the signal source (mV)、 Microvolt (V)、 nanovolt (nV) The small signal of level is amplified to the level of 100V or even kV , Used to drive piezoelectric ceramics 、 transducer 、 Coil isocapacity 、 Inductive load amplifier . Emphasize output power .

The above contents are tested by Aetna Agitek I'll share with you the difference between preamplifier and power amplifier , I believe you have a general understanding , If you want to know more , Consult Aetna testing http://www.agitek.com.cn