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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Google Plus and Facebook. 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.

Linear Integrated Circuits Applications Log And Anti Log Amplifiers

Project Using and 4. According to the virtual short conceptthe voltage at the inverting input terminal of op-amp will be equal to the voltage angilog at its non-inverting input terminal.

The figure of anti-logarithmic amplifier using matched diode is shown in figure below. Gain of logarithmic amplifier. 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.


logarthmic, anti logarthmic amplifiers

Two matched transistors is used usinng as shown in figure, where input is given to the non-inverting amplifier pin of first op-amplifier A1. Easy Electronic Projects 5.

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.

Complete Electrical Symbol 3.

logarthmic, anti logarthmic amplifiers | ECE Tutorials

Your email address will not be published. As we know that. 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.

You can connect with me on: Hence applying KCL at inverting terminal of opamp, 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.

Observe that the left hand side terms of both equation 1 and equation usihg are same.

Applying KCL at inverting node of opamp we get. Please note that these amplifiers fall under non-linear applications. As we know that is very small. A simple Anti log amplifier is shown below. Here a general purpose NPN transistor is connected to inverting input of op-amp.


Anti log amplifier is one which provides output proportional to the anti log i. The logarithmic circuit can be redrawn as follows. Gain of Anti log amplifier. This chapter discusses about the Logarithmic amplifier and Anti-Logarithmic amplifier in detail.

The circuit arrangement for Antilogarithmic amplifier is illustrated in figure 1. The anti log amplifier can be redrawn as follows. It means zero zmplifier is applied to its non-inverting input terminal. A logarithmic amplifieror a log amplifieris an electronic circuit that produces an output that is proportional to the logarithm of the applied input. Leave a Reply Cancel reply Your email address will not be published.

Now putting the value of collector current of transistor I C in equation 1. Best Arduino Projects 2.

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 op-amp A2 in reverse bias mood as shown in figure 2. Assuming both transistors are matched.