Logarithmic amplifier chips produce an output voltage that is directly proportional to the logarithm of the input voltage. Logarithmic amplifiers or log amplifiers are used mainly in applications that require the compression of signals, such as in video and audio equipment. A logarithmic amplifier chip is a log amplifier which requires components that are not part of a standard integrated circuit (IC). These components are designed to reduce temperature effects, accept voltage and current inputs that are bipolar, and protect base-emitter junctions that are inherent to all bipolar junction transmitters (BJTs). Trans-diode circuits, an important part of semiconductor amplifiers, may oscillate due to feedback elements. Consequently, logarithmic amplifier chips are unstable and may require the use of specialized circuit techniques. The connection of BJTs in logarithmic amplifier chips improves stability and response time, and permits easy changes in polarity.
Antilog amplifiers or exponential amps perform an inverse function to log amplifiers and logarithmic amplifier chips. With antilogarithmic amplifiers, both trans-diodes and transistors are connected to a diode, but the output voltage is equal to the ratio of twin voltage measures. The use of both log amps and antilog amps allows for the computation of analog signals. The computations that logarithmic amplifier chips perform include multiplication, division, modulus, and root functions.
Logarithmic amplifier chips are used in aircraft and electrical systems, sensors, and communications equipment. They are also used in radio frequency (RF) and intermediate frequency (IF) devices such as modems, telecommunications hardware, transceivers, switches, and converters. Suppliers of logarithmic amplifier chips may also manufacture electronic components such as transistors, diodes, and printed circuit boards (PCB). They may also manufacture power operational amplifiers (POA), devices used to increase the power of low-level signals in applications that drive low impedances or reactive loads. POAs dissipate excess energy as heat, deliver extensive current, and can sustain relatively high supply voltages.