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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Applying Antilog on both sides we amplifieg. Leave a Reply Cancel reply Your email address will not be published. Observe that the left hand side terms of both equation 1 and equation 3 are same. Project Using and 4. As we know that is very small.

## Antilogarithmic Amplifier | Derivation

Anti log amplifier is one which provides output proportional to the anti log i. Using the concept of virtual short between the input terminals of an opamp the voltage at inverting terminal will be zero volts.

Easy Electronic Projects 5. Electronic Game and Fun Projects. Gain of logarithmic amplifier. This section discusses about the op-amp based logarithmic amplifier in detail.

Please note that these amplifiers fall under non-linear applications. You can connect with me on: An op-amp based logarithmic amplifier produces a voltage at the output, which is amplifjer to the logarithm of the voltage applied to the resistor connected to its inverting terminal.

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. It is obvious from the circuit shown above that negative feedback is provided from output to inverting terminal.

An anti-logarithmic amplifieror an anti-log amplifieris an electronic circuit that produces an output amplifie is proportional to the anti-logarithm of the applied input.

Thus we can write. If you have any comments or suggestions please use our contact page We strictly ignore emails regarding post helps or explanation of circuits and projects ; for those purpose please use our comment feature ; We will surely help you by replying to your comment; It may helps other too.

It means zero volts is applied to its non-inverting input terminal. That means zero volts is applied at the non-inverting input terminal of the op-amp.

### Basic Antilog Amplifier Using Diode – EEEGUIDE

From the figure we can also conclude that transistor base emitter voltage V BE is equivalent input voltage V i i. The logarithmic circuit can be redrawn as follows. According to the virtual short conceptthe voltage at the inverting input terminal of an op-amp will be equal to the voltage ahtilog its non-inverting input terminal.

The output is depending upon output current of transistor and feedback resistor. Antilogarithmic amplifier is one whose output is antilogarithmic exponential of input.

In the above circuit, the non-inverting input terminal of the op-amp is connected to ground. 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.

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. The anti log amplifier can be redrawn as follows. Best Arduino Projects 2. As we know that.

A resistor is connected in feedback path. The circuit diagram of logarithmic amplifier is as shown below. The figure of anti-logarithmic amplifier using matched diode is shown in figure below. V is voltage applied across diode; V t is the voltage equivalent of temperature. The output voltage expression becomes.

Applying KCL at inverting node of opamp we get. This section discusses about the op-amp based anti-logarithmic amplifier in detail. So, the voltage at the inverting input terminal will be zero volts. This chapter discusses about the Logarithmic amplifier and Anti-Logarithmic amplifier in detail. Logarithmic amplifier operation The circuit diagram of logarithmic amplifier is as shown below logarithmic amplifier.

Voltage at inverting pin of op-amp A1 is potentially equal to voltage at non-inverting input of op-amp i.

## logarthmic, anti logarthmic amplifiers

I edit and author this site. 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. Gain of Anti log amplifier. Like logarithmic amplifierantilogarithmic is also a non-linear amplifier. Hence applying KCL at inverting terminal of opamp, we get. Now putting the value of collector current of transistor I C in equation ammp.

Assuming both transistors are matched. A simple Anti log amplifier is shown below. Since the non inverting terminal of opamp is at ground potential.

So, the voltage at its inverting input terminal will be zero volts. You May Also Like. Here a general purpose NPN transistor is connected to inverting input of op-amp.