### LOG ANTILOG AMPLIFIERS PDF

Introduction Log and Antilog Amplifiers are non-linear circuits in which the output voltage is proportional to the logarithm (or exponent) of the input. Log and Antilog Amplifiers are non-linear circuits in which the output voltage is proportional to the logarithm (or exponent) of the input. ❖ It is well known that. 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.

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This may be ensured by using a rectifier and filter to condition the input signal before applying it to the log amp input. You’ve simulated it, so why do you ask if it works for you? 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.

Your email address will not be published. Hence applying KCL at inverting terminal of opamp, we get. According to the virtual short conceptthe voltage at the inverting input terminal of an op-amp will be equal to the voltage at its non-inverting input terminal. Tony EE rocketscientist 62k 2 21 A log amplifier is an amplifier for which the output voltage V out is K times the natural log of the input voltage V in.

This section discusses about the op-amp based logarithmic amplifier in detail. Gain of Anti log amplifier. IC log amps may cost about ten times the components needed to build a discrete-component log amp. It is called four-quadrant since inputs and output can be positive or antioog.

## Log and AntiLog Amplifiers

Amplifirs basic circuits needs additional components to improove the overall performance, i. 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.

This is the basic layout of the circuit: Does loy seem reasonable? SPICE simulation of voltage multiplier using log and antilog amplifier. To design a logarithm amplifier circuit, high performance op-amps like LM, LM, LM are commonly used and a compensated logarithm amplifier may include more than one.

Electronic amplifiers Electronics stubs. The circuit diagram of logarithmic amplifier is as shown below. This relationship is shown in the following formula: Views Read Edit View history. A simple Anti log amplifier is shown below.

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

But this depends on your thermal design. Using the concept of virtual short between the input terminals of an opamp the voltage at inverting terminal will be zero volts.

It is well known that some processes such as amplidiers and division, can be performed by addition and subtraction of ajplifiers. Post Your Answer Discard By clicking “Post Your Answer”, you acknowledge that you have antilot our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies.

Logarithmic amplifier operation The circuit diagram of logarithmic amplifier is as shown below logarithmic amplifier. 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.

By using this site, you agree to the Terms of Use and Privacy Policy. Omitting R1 yields a currentinput log amp.

### Log and AntiLog Amplifiers

The final output is developed by an inverting amplifier amplifierx a voltage gain of —K2. Then, by taking the antilogarithm, you get the product of the two input voltages as indicated in the following equations: 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.

It means zero volts is applied to its non-inverting input terminal. 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.

So, the voltage at the inverting input terminal will be zero volts. So, the voltage at its inverting input terminal will be zero volts. The source impedance of voltage signals applied to the circuit must be small compared to R1.

Unclear what you’re asking.