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

Now putting the value of collector current of transistor I C in equation 1. That means zero volts is applied at the non-inverting input terminal of the op-amp. 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 amplfier to the diode connected to its inverting terminal.

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Logarithmic amplifier gives the output proportional to the logarithm of input signal. I edit and author this site. Electronic Game and Fun Projects.

logarthmic, anti logarthmic amplifiers

Voltage at inverting pin of op-amp A1 is potentially equal to voltage at non-inverting input of op-amp i. Thus, thermal voltage of 1 st transistor oop 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.

The figure of anti-logarithm amplifier is shown in figure 3. Ampliffier 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. Antilogarithmic amplifier is one whose output is antilogarithmic exponential of input.

Log And Anti Log Amplifiers

This section discusses about the op-amp based logarithmic amplifier in detail. Gain of logarithmic amplifier. Like logarithmic amplifierantilogarithmic is also a non-linear amplifier.

So, the voltage at its inverting input terminal will be zero volts. This section discusses about the op-amp based anti-logarithmic amplifier in amplfier. Project Using and 4.

Basic Antilog Amplifier Using Diode – EEEGUIDE

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. Applying Antilog on both sides we get. In the above circuit, the non-inverting input terminal of the op-amp is connected to ground. A logarithmic amplifieror a log amplifieris an electronic circuit that produces an output that is proportional to the logarithm of the applied input.


Thus we can write. You May Also Like. The circuit arrangement for Antilogarithmic amplifier is illustrated in figure 1. Applying KCL at inverting node of opamp we get.

Hence applying KCL at inverting terminal of opamp, we get. From the figure we can also conclude that transistor base amplifire voltage V BE is equivalent input voltage V i i.

The circuit diagram of logarithmic amplifier is as shown below. So, the voltage at the inverting input terminal will be zero volts.

Observe that the left hand side terms of both equation 1 and equation 3 are same. The figure of anti-logarithmic amplifier antilot matched diode is shown in figure below. A resistor is connected in feedback path.

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. Best Arduino Projects 2.