## ANTILOG AMPLIFIER USING OP AMP PDF

##### May 24, 2021 | by admin

a diode used in the feedback loop of an operational amplifier is forward biased by a constant current loop of an op-amp. Antilog is inverse operation of log operation so; antilog amplifiers can be operation. Log Amplifier using Diode. Fig 1. Antilogarithmic Amplifier using Single Transistor. The circuit Here a general purpose NPN transistor is connected to inverting input of op-amp. Basic Antilog Amplifier Using Diode The circuit diagram of basic antilog amplifier using diode As op-amp input current is zero, the current I must be same as If.

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In the circuit shown above, the non-inverting input terminal of the op-amp is connected to ground. Two matched diodes are used here, where one diode D 1 is connected in feedback path and second diode D 2 is connected to inverting input of zntilog A2 in reverse bias mood as shown in figure 2. The logarithmic circuit can be redrawn as follows.

Observe that the left hand side terms of both apmlifier 1 and equation 3 are same. A logarithmic amplifieror a log amplifieris an electronic circuit that antiog an output that is proportional to the logarithm of the applied input. 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.

An op-amp based logarithmic amplifier produces a voltage at the output, which is proportional to the logarithm of the voltage applied to the resistor connected to its inverting terminal. In the above circuit, the non-inverting input terminal of the op-amp is connected to ground. The output voltage expression becomes. Like logarithmic usignantilogarithmic is also a non-linear amplifier.

### Basic Antilog Amplifier Using Diode – EEEGUIDE

Two matched transistors is used here as shown in figure, where input is given to the non-inverting amplifier pin of first op-amplifier A1. The circuit diagram of logarithmic amplifier is as shown below. It means zero volts is applied to atilog non-inverting input terminal. Voltage at inverting pin of op-amp A1 is potentially equal to antliog at non-inverting input of op-amp i.

The figure of anti-logarithm amplifier is shown in figure 3. As we know that is very small. I edit and author this site. From the figure we can also conclude that transistor base emitter voltage V BE is equivalent input voltage V i i. This section discusses about the oop based anti-logarithmic amplifier in detail. Antilogarithmic amplifier is one whose output is antilogarithmic exponential of input.

As we know that. Easy Electronic Projects 5. The circuit arrangement for Antilogarithmic amplifier is illustrated in figure 1. You May Also Like. Now putting the value of collector current of transistor I C in equation 1. Electronic Game and Fun Projects.

This section discusses about the op-amp based logarithmic amplifier in detail. Best Arduino Projects 2. A resistor is connected in feedback path. Thus, we can write. The output is depending upon output current of transistor and feedback resistor.

## Antilogarithmic Amplifier | Derivation

Complete Electrical Symbol 3. Applying KCL at inverting node of opamp we get. Project Using and 4. Using the concept of virtual short between the input terminals of an opamp the voltage at inverting terminal will be zero volts.

Your email address will not be published. It is obvious from the circuit shown above that negative feedback is provided from output to inverting terminal. Anti log amplifier is one which provides output proportional to the anti log 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.

Assuming both diode and matched thus material constant, thermal voltage of diode and saturation current of diode is also same. The anti log amplifier can be redrawn as follows. A simple Anti log amplifier is shown below.

### Antilogarithmic Amplifier | Derivation

Assuming both transistors are matched. 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.

Logarithmic amplifier operation The circuit diagram of logarithmic amplifier is as shown below logarithmic amplifier. Hence applying KCL at inverting terminal of opamp, we get.

Google Plus and Facebook. According to the virtual short conceptthe voltage at the inverting input terminal of op-amp will be antllog to the anfilog present at its non-inverting input terminal. That means zero volts is applied at the non-inverting input terminal of the op-amp. Thus we can write. This chapter discusses about the Logarithmic amplifier and Anti-Logarithmic amplifier in detail.

Logarithmic amplifier gives the output proportional to the logarithm of input signal. The figure of anti-logarithmic amplifier using matched diode is shown in figure below.

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. Gain of Anti log amplifier. Gain of logarithmic amplifier.