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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Sign up or log in Sign up using Google. Amplifoer similar question from a month ago: Hence applying KCL at inverting terminal of opamp, we get. But this depends on your thermal design.

Log And Anti Log Amplifiers

A simple Anti log amplifier is shown below. It is well known that some processes such as multiplication and division, can be performed by addition and subtraction of logs. The logarithmic amplifidr can be redrawn as follows. Alternatively, the log amp can be preceded by a precision current inverter.

Antilog amps are used together with log amps to perform analog computation. This relationship is shown in the following formula: To get the logarithm of a signal voltage use a Log amplifier. Post Your Answer Discard By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of anvprivacy policy and cookie policyand that your continued use of the website is subject to these policies.

Observe that the left hand side terms of both equation 1 and equation 3 are same. The analysis is the same as above for the transdiode connection, but the logarithmic range is limited to four or five decades because the base current adds to the collector current. This chapter discusses about the Logarithmic amplifier and Anti-Logarithmic amplifier in detail. Leave a Reply Cancel reply Your email address will not be published. Gain of logarithmic amplifier. You have 4 volts and 5 volts as your inputs.


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

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 n-p-n transistors www. One usually starts with a spec for Input and Output voltage range and max error vs antiloh. Negative voltages or currents can be first rectified and then applied to the log amp, but this adds the errors from the rectifier. Tony EE rocketscientist 62k 2 21 This is natilog basic layout of the circuit: This section discusses about the op-amp based anti-logarithmic amplifier in detail.

V is voltage applied across diode; V t is the voltage equivalent of temperature. Unclear what you’re asking. In the circuit shown above, the non-inverting input terminal of the op-amp is connected to ground. Automated Classification of internet video content. The system bandwidth is narrower for small signals because emitter resistance increases for small currents.

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Log and AntiLog Amplifiers

This section discusses about the op-amp based logarithmic amplifier in detail. Your email address will not be published. Please think about what you are doing in your simulation. Documents Flashcards Grammar checker.

logarthmic, anti logarthmic amplifiers | ECE Tutorials

They have numerous applications in electronics, such as: To investigate its stability, refer to the incremental model, where the BJT has been replaced by its common-base smallsignal model. DIT offerings in year 3 and 4. Please note that these amplifiers fall under non-linear applications. According to the virtual short conceptthe voltage at the inverting input terminal of an op-amp will be equal to ampligier voltage at its non-inverting input terminal.


That means zero volts is applied at the non-inverting input terminal of the op-amp. Ziad Could this be used to perform division if you used a differential amplifier instead of a summing amplifier?

Regression-based Active Learning for Fraud Detection. Then verify your design specs with sweeping voltages on loy inputs and compute the gain and offset errors vs input. Constant terms are omitted for simplicity. Applying Antilog on both sides we get.

Log and AntiLog Amplifiers

Log-Antilog Log and antilog amp circuits include the same elements but arranged in different feedback configurations. Some integrated log amps have uncommitted elements allowing us to implement antilog amps. So this is another tradeoff for logg size vs bandwidth vs temp rise. Consider the voltage-input transdiode. 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.

Gain of Anti log amplifier. Applying KCL at inverting node of opamp we get.

Anti log amplifier is one which provides output proportional to the anti log i. Then a properly working multiplier should give you anhilog volts out.

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