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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## Log and AntiLog Amplifiers

Hence applying KCL at inverting terminal of opamp, we get. Observe that the antilo hand side terms of both equation 1 and equation 3 are same. Then a properly working multiplier should give you 20 volts out.

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. Post as a guest Name.

Omitting R1 yields a currentinput log amp. Sign up using Facebook. You have 4 volts and 5 volts as your inputs. Logarithmic amplifier gives the output proportional to the logarithm of input signal. The anti log amplifier can be redrawn as follows.

### Log and AntiLog Amplifiers

Then finally choose a max temp difference of the log and antilog diodes to avoid gain and offset errors. Such circuit techniques are used in integrated log amps: Figure next slide shows the use of a second, matched, transistor for offset compensation and a ad gain for gain compensation.

It means zero volts is applied to its non-inverting input terminal. So this is another tradeoff for diode size vs bandwidth vs temp rise. Tony EE rocketscientist 62k 2 21 Antilog amps are used together with log amps to perform analog computation.

Very similar question from a month ago: This section discusses about the op-amp based anti-logarithmic amplifier in detail. A logarithmic amplifieror a log amplifieris an electronic circuit that produces an output that is proportional to the logarithm of the applied input.

The bulk size and Pd rating of the diode affects the thermal resistance and bulk resistance lot ESR, and also junction capacitance and bandwidth. This relationship is shown in the following formula: 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.

In the circuit shown above, the non-inverting input terminal of the op-amp is connected to ground.

## logarthmic, anti logarthmic amplifiers

Constant terms are omitted for simplicity. Matched temperature by thermal coupling is desired or minimize self heating for low T rise. It is called four-quadrant since inputs and output can be positive or negative. Automated Classification of internet video content. 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: They have numerous applications in electronics, such as: So, the voltage at its inverting input terminal will be zero volts.

SPICE simulation of voltage multiplier using log and antilog amplifier. The source impedance of voltage signals applied to the circuit must be small compared to R1. You’ve simulated it, so why do you ask if it works for you? Temperature compensation must correct both error sources. Logarithmic amplifier operation The circuit diagram of logarithmic xntilog is as shown below logarithmic amplifier.

Then, by taking the antilogarithm, you get the product of the two input voltages as indicated in the following equations: These basic circuits needs additional components to improove the overall performance, i. This chapter discusses about the Logarithmic amplifier and Anti-Logarithmic amplifier in detail.

Applying Antilog on both sides we get. This is the basic layout of the circuit: In the above circuit, the non-inverting input terminal of the op-amp antiog connected to ground. I’m trying to build an analog multiplier that takes any two voltages and produces the product for them.

### Linear Integrated Circuits Applications Log And Anti Log Amplifiers

Email Required, but never shown. Documents Flashcards Grammar checker. Anti log amplifier is one which provides output proportional to the anti log i. That means zero volts is applied at the non-inverting input terminal of the op-amp. It is well known that some processes such as multiplication and division, can be performed by addition and subtraction of logs. So, the voltage at the inverting input terminal will be zero volts.

A simple Anti log amplifier is shown below.