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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The figure of anti-logarithm amplifier is shown in figure 3. Project Using and 4. V is voltage applied across diode; V t is the voltage equivalent of temperature. Please note that these amplifiers fall under non-linear applications.

A logarithmic amplifieror a log amplifieris an ampilfier circuit that produces an output that is proportional to the logarithm of the applied input. Now putting the value of collector current of transistor I C in equation 1.

### Antilogarithmic Amplifier | Derivation

That means zero volts is applied at the non-inverting input terminal of the op-amp. A simple Anti log amplifier is shown below. Observe that the left hand side terms of both equation 1 and equation 3 are same. As we know that is very small.

## logarthmic, anti logarthmic amplifiers

It means zero volts is applied to its non-inverting input terminal. Easy Electronic Projects 5. Thus, we can write.

Thus we can write. You can connect with me on: Leave abtilog Reply Cancel reply Your email address will not be published. Applying Antilog on both sides we get.

Electronic Game and Fun Projects. So, the voltage at the inverting input terminal amplofier be zero volts. Gain of Anti log amplifier. Since the non inverting terminal of opamp is at ground potential. As we know that. From the figure we can also conclude that transistor base emitter voltage V BE is equivalent input voltage V i i. So, the voltage at its inverting input terminal will be zero volts.

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. Logarithmic amplifier operation The circuit diagram of logarithmic amplifier is as shown below logarithmic amplifier. You Ip Also Like. Best Arduino Projects 2.

## Antilogarithmic Amplifier | Derivation

Using the concept of virtual short between the input terminals of an opamp the voltage at inverting terminal will be zero volts. The circuit arrangement for Antilogarithmic amplifier is illustrated in figure 1. Antilogarithmic amplifier is one whose output is antilogarithmic exponential of input. I edit and author this site. The anti log amplifier can be redrawn usinv follows.

It is obvious from the circuit shown above that negative feedback is provided from output to inverting terminal. Complete Electrical Symbol 3. This chapter discusses about the Logarithmic amplifier and Anti-Logarithmic amplifier in detail. Logarithmic amplifier gives the output usinh to the logarithm of input signal. In the circuit shown above, the non-inverting input antioog of the op-amp is connected to ground.

Anti log amplifier is one which provides output proportional to the anti log i. 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. 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.

Here a general purpose NPN transistor is connected to inverting input of op-amp.