Antilog amplifiers along with log amplifiers are used to perform analogue computations on the input signals. The circuit of an antilog amplifier. But if diode current is too low then the OP Amp input offsets become Then finally choose a max temp difference of the log and antilog diodes. EXPERIMENT 8: Log and Antilog Amplifiers. Objectives: To understand the behavior of logarithmic and antilogarithmic amplifiers. Materials and Equipment.

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It is obvious from the circuit shown above that negative feedback is provided from output to inverting terminal.

Log And Anti Log Amplifiers

Does this seem reasonable? An op-amp based logarithmic amplifier produces a voltage at antliog output, which is proportional to the logarithm of the voltage applied to the resistor connected to its inverting terminal. This chapter discusses about the Logarithmic amplifier and Anti-Logarithmic amplifier in amplifiet. The bulk size and Pd rating of the diode affects the thermal resistance and bulk resistance or ESR, and also junction capacitance and bandwidth.

Hence applying KCL at inverting terminal of opamp, we get.

The source impedance of voltage signals applied to the circuit must be small compared to R1. Antilog amps are used together with log amps to perform analog computation. It is well known that some processes such as multiplication and division, can be performed by addition and subtraction of logs.


Matched temperature by thermal antjlog is desired or minimize self heating for low T rise.

The electronic circuits which perform the mathematical operations such as logarithm and anti-logarithm exponential with an amplification are called as Logarithmic amplifier and Anti-Logarithmic amplifier respectively. These basic circuits needs additional components to improove the overall performance, i.

Please note that these amplifiers fall under non-linear applications. According to the virtual short conceptthe voltage at the inverting input terminal of op-amp will be equal to the voltage present at its non-inverting input terminal.

Consider the voltage-input transdiode. So, the voltage at its inverting input terminal will be zero volts. The anti log amplifier can be redrawn as follows. Gain of Anti log amplifier. Post as a guest Name. Anti log amplifier is one which provides output proportional to the anti log i. A logarithmic amplifieror a log amplifieris an electronic circuit that produces an output that is proportional to the logarithm of the applied input.

Company Table Recruiting Disciplines. Email Required, but never shown. An op-amp based anti-logarithmic amplifier produces a voltage at the output, which is proportional to the anti-logarithm of the voltage that is applied to the diode connected to its inverting terminal. As such, they can vary over a wide range of values. Applying KCL at inverting node of opamp we get.

It is called four-quadrant since inputs and output can be positive or negative. Omitting R1 yields a currentinput log amp. Sign up or log in Sign up using Google.


Linear Integrated Circuits Applications Log And Anti Log Amplifiers

The K values control the R value which controls the diode current which can lead to errors if there is self heating which is the NTC Shockley Effect.

It means zero volts is applied to its non-inverting input terminal. Constant terms are omitted for simplicity. Automated Classification of internet video content. An anti-logarithmic amplifieror an anti-log amplifieris an electronic circuit that produces an output that is proportional to the anti-logarithm of the applied input.

Ziad Could this amplifieg used to perform division if you used a differential amplifier instead of a summing amplifier?

Gain of logarithmic amplifier. I’m trying to build an analog multiplier that takes any two voltages and produces the product for them. Then determines the required input bias current and offset must be to achieve this. Alternatively, the log amp can be preceded by a precision sntilog inverter. The logarithmic circuit can be redrawn as follows.

Using a p-n-p transistor changes the polarity of input signals acceptable but limits the logarithmic range because of the degraded performance of p-n-p transistors compared to anc transistors www. By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies.