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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### Linear Integrated Circuits Applications Log And Anti Log Amplifiers

It is obvious from the circuit shown above that negative feedback is provided from output to inverting terminal. To get the logarithm of a signal voltage use a Log amplifier. Omitting R1 yields a currentinput log amp. Using a p-n-p transistor changes the polarity of input signals acceptable but limits the sntilog range because of the degraded performance of p-n-p transistors compared to n-p-n transistors www.

## Log And Anti Log Amplifiers

Antilog amps are used together with log amps to perform analog computation. Post Your Answer Discard By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of zmplifierprivacy policy and cookie policyand that your continued use of the website is subject to these policies.

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Home Questions Tags Users Unanswered. 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.

## Log and AntiLog Amplifiers

D1 protects the base-emitter junction from excessive reverse voltages. Very similar question from a month ago: I’m trying to build an analog multiplier that takes any two voltages and produces the product for them This is the basic layout of the circuit: 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.

In the above circuit, the non-inverting input terminal of the op-amp is connected to ground. This relationship is shown in the following formula: One usually starts with a spec for Input and Output voltage range and max error vs input.

Matched temperature by thermal coupling is desired or minimize self heating for low T rise. Automated Classification of internet video content. 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. Sign up or log in Sign up using Google. Hence applying KCL at inverting terminal of opamp, we get. So, the voltage at amplifire inverting input terminal will be zero volts.

The current inverter in Amplifidr below uses two matched n-p-n transistors and a precision op amp to achieve accurate current inversion.

Please note that these amplifiers fall under non-linear applications. That means zero volts is applied at the non-inverting input terminal of the op-amp. This chapter discusses about the Logarithmic amplifier and Anti-Logarithmic amplifier in detail. In the circuit shown above, the non-inverting input terminal of the op-amp is connected to ground. Company Table Recruiting Disciplines. It is well known that some processes such as multiplication and division, can be performed by addition and subtraction of logs.

Alternatively, the log amp can be preceded by a precision current inverter.

Ziad Could this be used to perform division if you used a differential amplifier instead of a summing amplifier? The final output is developed by an inverting amplifier with a voltage gain of —K2. Sign up using Facebook. The diode dynamic resistance also drops with rising log current until saturated where the bulk resistance limits the minimum resistance.

### logarthmic, anti logarthmic amplifiers | ECE Tutorials

But if diode current is too low then the OP Amp input offsets become significant compared the the log1, log2 outputs. Consider the voltage-input transdiode. Please think about what you are doing in your simulation. A simple Anti log amplifier is shown below.

An op-amp based logarithmic amplifier produces a voltage at the output, which is proportional to the logarithm of the an applied to the resistor connected to its inverting terminal.

Applying KCL at inverting node of opamp we get. This is the basic layout of the circuit: Applying Antilog on both sides we get.

Then finally choose a max temp difference of the log and antilog diodes to avoid gain and offset errors.