If log M = x, then M is called the antilogarithm of x and is written as M = antilog x.
For example, if log 39.2 = 1.5933, then antilog 1.5933 = 39.2.
Logarithms & antilogarithms + How to find Logs & antilogs using Log Table. CALCULATIONS USING LOGARITHMIC TABLE (Log Table). U didn't even use the anti-log table to explain it. In brief the explanation of ant-logs sucked, waste of time.
If the logarithmic value of a number be given then the number can be determined from the antilog-table. Antilog-table is similar to log-table; only difference is in the extreme left-hand column which ranges from .00 to .99.
Example on antilogarithm:
1. Find antilog 2.5463.
Solution:
Clearly, we are to find the number whose logarithm is 2.5463. For this consider the mantissa .5463. Now find .54 in the extreme left-hand column of the antilog-table (see four-figure antilog-table) and then move horizontally to the right to the column headed by 6 of the top-most row and read the number 3516. Again we move along the same horizontal line further right to the column headed by 3 of mean difference and read the number 2 there. This 2 is now added to the previous number 3516 to give 3518. Since the characteristic is 2, there should be three digits in the integral part of the required number.
Therefore, antilog 2.5463 = 351.8.
1. Find antilog 2.5463.
Solution:
Clearly, we are to find the number whose logarithm is 2.5463. For this consider the mantissa .5463. Now find .54 in the extreme left-hand column of the antilog-table (see four-figure antilog-table) and then move horizontally to the right to the column headed by 6 of the top-most row and read the number 3516. Again we move along the same horizontal line further right to the column headed by 3 of mean difference and read the number 2 there. This 2 is now added to the previous number 3516 to give 3518. Since the characteristic is 2, there should be three digits in the integral part of the required number.
Therefore, antilog 2.5463 = 351.8.
2. If log x = -2.0258, find x.
Solution:
In order to find the value of x using antilog-table, the decimal part (i.e., the mantissa) must be made positive. For this we proceed as follows:
log x = -2.0258 = - 3 + 3 - 2.0258
= - 3 + .9742 =3.9742
Therefore, x = antilog 3.9742.
Now, from antilog table we get the number corresponding to the mantissa
.9742 as (9419 + 4) = 9423.
Again the characteristic in log x is (- 3).
Hence, there should be two zeroes between the decimal point and the first significant digit in the value of x.
Therefore, x = .009423.
In order to find the value of x using antilog-table, the decimal part (i.e., the mantissa) must be made positive. For this we proceed as follows:
log x = -2.0258 = - 3 + 3 - 2.0258
= - 3 + .9742 =3.9742
Therefore, x = antilog 3.9742.
Now, from antilog table we get the number corresponding to the mantissa
.9742 as (9419 + 4) = 9423.
Again the characteristic in log x is (- 3).
Hence, there should be two zeroes between the decimal point and the first significant digit in the value of x.
Therefore, x = .009423.
●Mathematics Logarithm
Logarithms
11 and 12 Grade Math
From Antilogarithm to HOME PAGE
11 and 12 Grade Math
From Antilogarithm to HOME PAGE
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Antilog amplifiers along with log amplifiers are used to perform analogue computations on the input signals. The circuit of an antilog amplifier. 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. EXPERIMENT 8: Log and Antilog Amplifiers. Objectives: To understand the behavior of logarithmic and antilogarithmic amplifiers. Materials and Equipment.
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According to the virtual short conceptthe voltage at the inverting input terminal of an op-amp will be equal to the voltage at its non-inverting input terminal. Since the non inverting terminal of opamp is at ground potential. Temperature compensation must correct both error sources. The source impedance of voltage signals applied to the circuit must be small compared to R1.
It is obvious from the circuit shown above that negative feedback is provided from output to inverting terminal.
So, the voltage at the inverting input terminal will be zero volts. Please think about what you are doing in your simulation. An op-amp based logarithmic amplifier produces a voltage at the output, which is proportional to the logarithm of the voltage applied to the resistor connected to its inverting terminal.
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. Applying KCL at inverting node of opamp we get.
The logarithmic circuit can be redrawn as follows. Figure next slide shows the use of a second, matched, transistor for offset compensation and a temperature-dependent gain for gain compensation. It means zero volts is ajd to its non-inverting input terminal. Post Your Answer Discard By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies.
IC log amps may cost about ten times the components needed to build a discrete-component log amp. Does this seem reasonable? It is well known that some processes such as multiplication and division, can be performed by addition and subtraction of logs.
The electronic circuits which perform the mathematical operations such as logarithm and andd exponential with an amplification are called as Logarithmic amplifier and Anti-Logarithmic amplifier respectively.
Log and AntiLog Amplifiers
Alternatively, the log amp can be preceded by a precision current inverter. Constant terms are omitted for simplicity. Sign up using Facebook.
This relationship is shown in the following formula: Sign up or log in Sign up using Google. Post as a guest Name.
logarthmic, anti logarthmic amplifiers | ECE Tutorials
But if diode current is too low then the OP Amp input offsets become significant compared the the log1, log2 outputs. Ziad Zmplifier this be used to perform division if you used a differential amplifier instead of a summing amplifier? But this depends on your thermal design.
The two output voltages from the log amplifiers are added and inverted by the unity-gain summing amplifier to produce the following result: Using a p-n-p transistor changes the polarity of input signals acceptable but limits the logarithmic range because of the degraded performance oog p-n-p transistors compared to n-p-n transistors www.
SPICE simulation of voltage multiplier using log and antilog amplifier. Such circuit antioog are used in integrated log amps: In the circuit shown above, the non-inverting input terminal of the op-amp is connected to ground. I know there is problem with the last stage, the last opamp should give me gain: I’m trying to build an analog multiplier that takes any two voltages and produces the product for them This is the basic layout of the circuit: You have 4 volts and 5 volts as your ahtilog.
Logarithmic amplifier operation The circuit diagram of logarithmic amplifier is as shown below logarithmic amplifier. By summing the outputs of xntilog log amplifiers, you get the logarithm of the product of the two original input voltages. 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.
Log-Antilog Log and antilog ampllifier circuits include the same elements but arranged in different feedback configurations. Please note that these amplifiers fall under non-linear applications. Using the concept of virtual short between the input terminals of an opamp the voltage at inverting terminal will be zero volts.
Log And Anti Log Amplifiers
It is called four-quadrant since inputs and output can be positive or negative. Automated Classification of internet video content. Sign up using Email and Password. Then, by taking the antilogarithm, you get the product of the two input voltages as indicated in the following equations: Consider the voltage-input transdiode.
Log and AntiLog Amplifiers
The current inverter in Figure below uses two matched n-p-n transistors and a precision op amp to achieve accurate current inversion. Omitting R1 yields a currentinput log amp.
This section discusses about the op-amp based anti-logarithmic amplifier in detail. Negative voltages or currents can be first rectified and then applied to the log amp, but this adds the errors from the rectifier. Home Questions Tags Users Unanswered.
Company Table Recruiting Disciplines. D1 protects the base-emitter junction from excessive reverse voltages. So this is another tradeoff for diode size vs bandwidth vs temp rise. V is voltage applied across diode; V t is the voltage equivalent of temperature.