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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Here a general purpose NPN transistor is connected to inverting input of op-amp. Your email address will not be published. The figure of anti-logarithm amplifier is shown in figure 3. Anti log amplifier is one which provides output proportional to the anti log i.

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

Thus, thermal voltage of 1 st transistor will be same to thermal voltage of 2 nd transistor and saturation current of 1 st transistor will be equal to saturation current of 2 nd transistor.

According to the virtual short conceptthe voltage at the inverting input terminal of an op-amp will be equal to the voltage antilig its non-inverting input terminal.

I edit and author this site. The output is depending upon output current of transistor and feedback resistor. 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.

V is voltage applied across diode; V t is the voltage equivalent of temperature. Electronic Game and Fun Projects. A logarithmic amplifieror a log amplifieris an electronic circuit that produces an output that is proportional to the logarithm of the applied input.

### Antilogarithmic Amplifier | Derivation

Best Arduino Projects 2. Like logarithmic amplifierantilogarithmic is also a non-linear amplifier. Thus, we can write. Easy Electronic Projects 5.

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Project Using and 4. Thus we can write.

So, the voltage at its inverting input terminal will be zero volts. Applying Antilog on both sides we get. 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.

## logarthmic, anti logarthmic amplifiers

The output voltage expression becomes. 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. Google Plus and Facebook. So, the voltage at the inverting input terminal will be zero volts. Complete Electrical Symbol 3.

This section discusses about the op-amp based logarithmic amplifier in detail. Please note that these amplifiers fall under non-linear applications.

Since the non inverting terminal of opamp is at ground potential. It is obvious from the circuit shown above that negative feedback is provided from output to inverting terminal.

As we know that is very small. This section discusses about the op-amp based anti-logarithmic amplifier in detail. Antilogarithmic amplifier is one whose output is antilogarithmic exponential of input.

Assuming both transistors are matched. 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. According to the virtual short conceptthe voltage at the inverting input terminal of op-amp will be equal ajplifier the voltage present at its non-inverting input terminal. This chapter discusses about the Logarithmic amplifier and Anti-Logarithmic amplifier in detail.

The circuit diagram of logarithmic amplifier is as shown below. In the circuit usng above, the non-inverting input terminal of the op-amp is connected to ground.