Introduction Log and Antilog Amplifiers are non-linear circuits in which the output voltage is proportional to the logarithm (or exponent) of the input. Log and Antilog Amplifiers are non-linear circuits in which the output voltage is proportional to the logarithm (or exponent) of the input. ❖ It is well known that. But if diode current is too low then the OP Amp input offsets become Then finally choose a max temp difference of the log and antilog diodes.

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The logarithm amplifier gives an output voltage which is proportional to the logarithm of applied input voltage. Please note that these amplifiers fall under non-linear applications.

Documents Flashcards Grammar checker. I know there is problem with the last stage, the last opamp should give me gain: The current inverter ampliciers Figure below uses two matched n-p-n transistors and a precision op amp to achieve accurate current inversion.

Log And Anti Log Amplifiers

I’m trying to build an analog multiplier that takes any aamplifiers voltages and produces the product for them. Some integrated log amps have uncommitted elements allowing us to implement antilog amps. It means zero volts is applied to its non-inverting input terminal.


Sign up using Facebook. The source impedance of voltage signals applied to the circuit must be small compared to R1.

Log and AntiLog Amplifiers

antiloog In the above circuit, the non-inverting input terminal of the op-amp is connected to ground. Anti log amplifier is one which provides output proportional to the anti log i.

It is well known that some processes such as multiplication and division, can be performed by addition and subtraction of logs. Using the concept of virtual short between the input terminals of an opamp the voltage at inverting terminal will be zero volts.

Tony EE rocketscientist 62k 2 21 This relationship is shown in the following antilogg 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. Amplkfiers terms are omitted for simplicity.

You have 4 volts and 5 volts as your inputs. Post as a guest Name. Then verify your design specs with sweeping voltages on the inputs and compute the gain and offset errors vs input. Observe that the left hand side terms of both equation anrilog and equation 3 are same. IC log amps may cost about ten times the components needed to build a discrete-component log amp.

The diode dynamic resistance also drops with rising log current until saturated where the bulk resistance limits the minimum resistance. To get the logarithm of a signal voltage use a Log antilov.


The anti log amplifier can qntilog redrawn as follows. As V in is positive, V out is obliged to be negative since the op amp is in the inverting configuration and is large enough to forward bias the emitter-base junction of the BJT keeping it in the active mode of operation. A simple Anti log amplifier is shown below.

Automated Classification of internet video content. Log-Antilog Log and antilog amp circuits include the same elements but arranged in different feedback configurations. You can help Wikipedia by expanding it. 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.

Log amplifier – Wikipedia

Gain of logarithmic amplifier. It is obvious from the circuit shown above that negative feedback is provided from output to inverting terminal. Company Table Recruiting Disciplines. Similarly the emitter saturation current varies significantly from one transistor to another and also with temperature.