# LOG AND ANTILOG AMPLIFIER PDF

November 24, 2020Antilog 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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So this is another tradeoff for diode size vs bandwidth vs temp rise. Since the non inverting terminal of opamp is at ground potential. Documents Flashcards Grammar checker. Ziad Could this be used to perform division if you used a differential amplifier instead of a summing amplifier?

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

Observe that the left hand side terms of both equation 1 and equation 3 are same. DIT offerings in year 3 and 4. You have 4 volts and 5 volts as your inputs. This section discusses about the op-amp based anti-logarithmic amplifier in detail. This section discusses about the op-amp based logarithmic amplifier in detail. Then determines the required input bias current and offset must be to achieve this.

V is voltage applied across diode; V t is the voltage equivalent of temperature. 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. That means zero volts is applied at the non-inverting input terminal of the op-amp.

## logarthmic, anti logarthmic amplifiers

This chapter discusses about the Logarithmic amplifier and Anti-Logarithmic amplifier in detail. Sign up or log in Sign up using Google. By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

Applying Antilpg at inverting node of opamp we get.

Some integrated log amps have uncommitted elements allowing us to implement antilog amps. Email Required, but never shown. The final output is developed by an inverting amplifier with a voltage gain of —K2. Gain of logarithmic amplifier. Matched temperature by thermal coupling is desired or minimize self heating for low Anc rise.

The source impedance of voltage signals applied to the circuit must be small compared to R1. According to the virtual short conceptthe amplifiet at the inverting input terminal of an op-amp will be equal to the voltage at its non-inverting input terminal. The anti log amplifier can be redrawn as follows. By summing the outputs of two log amplifiers, you get the logarithm of the product of the two original input voltages.

### Log and AntiLog Amplifiers

Log-Antilog Log and antilog amp circuits include the same elements but arranged in different feedback configurations. But if diode current is too low then the OP Amp input offsets become significant compared the the log1, log2 outputs. Omitting R1 yields a currentinput log amp. So, the voltage at its inverting input terminal will be zero volts.

They have numerous applications in electronics, such as: Constant terms are omitted antilpg simplicity. Applying Antilog on both sides we get. The logarithmic circuit can be redrawn as follows.

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.

So, the voltage at the inverting input terminal will be zero volts. Very similar question from a month ago: D1 protects the base-emitter junction from excessive reverse voltages. Negative voltages or currents can be first rectified and then applied to the log amp, but this adds the errors from the rectifier. Then verify your design specs with sweeping voltages on the inputs and compute the gain and offset errors vs input. Sign up using Facebook. Temperature compensation can be achieved by the same technique shown for log amps.

Then, by taking the antilogarithm, you get the product of the two input voltages as indicated in the following equations: I’m trying to build an analog multiplier that takes any two voltages and produces the product for them. 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: You’ve simulated it, so why do you ask if it works for you?