How to calculate the output voltage of half wave rectifier

A rectifier is a circuit that converts alternating contemporary (AC) to Direct contemporary (DC). An alternating contemporary modifications its path over time, however the direct contemporary flows constantly in a single path. In an ordinary rectifier circuit, we use diodes to rectify AC to DC. But this rectification technique can simplest be used if the enter voltage to the circuit is more than the ahead voltage of the diode which is generally 0.7V. We formerly defined diode-primarily based half-wave rectifier 1/2 of-wave rectifier and full-wave rectifier circuit.

To conquer this issue, the Precision Rectifier Circuit became introduced. The precision rectifier is every other rectifier that converts AC to DC, however in a precision rectifier we use an op-amp to atone for the voltage drop throughout the diode, this is why we aren’t dropping the 0.6V or 0.7V voltage drop throughout the diode, additionally, the circuit may be built to have a few advantages on the output of the amplifier as well.

So, in this tutorial, I am going to reveal to you the way you could build, test, apply, and debug a precision rectifier circuit with the usage of the op-amp. Alongside that, I can be discussing a few execs and cons of this circuit as well. So, without additional ado, permit`s get started.

What is a Precision Rectifier Circuit?

Before we recognize approximately the Precision Rectifier Circuit, permit’s make clear the fundamentals of the rectifier circuit.

Ideal Rectifier Circuit

The above determination indicates the traits of a perfect rectifier circuit with its switch traits. This implies while the enter sign is terrible, the output can be 0 volts and while the enter sign is nice the output will comply with the enter sign.

Practical Rectifier Circuit

The above determination indicates a sensible rectifier circuit with its switch traits. In a sensible rectifier circuit, the output waveform can be 0.7 volts much less than the implemented enter voltage, and the switch feature will seem like the determine proven withinside the diagram. At this point, the diode will simplest behavior if the implemented enter sign is barely more than the ahead voltage of the diode.

Now the fundamentals are out of the way, permit flip our recognition lower back to the precision rectifier circuit.

Working of Precision Rectifier

The above circuit indicates a basic, 1/2-of-wave precision rectifier circuit with an LM358 Op-Amp and a 1n4148 diode. To find out how an op-amp works, you could comply with this op-amp circuit.

The above circuit additionally indicates the enter and output waveform of the precision rectifier circuit, which is precisely identical to the enter. That’s due to the fact we’re taking the comments from the output of the diode and the op-amp compensates for any voltage drop throughout the diode. So, the diode behaves like a perfect diode.

Half Wave Precision Rectifier Circuit

Now withinside the above photo, you could see what occurs while a nice and a terrible 1/2 of the cycle of the enter sign is implemented withinside the enter terminal of the Op-Amp. The circuit additionally indicates the switch traits of the circuit.

But in a sensible circuit, you may now no longer get the output as proven withinside the above determined, permit me to let you know why?

Half Wave Precision Rectifier Waveform

In my oscilloscope, the yellow sign withinside the enter, and the inexperienced sign is the output. Instead of having a 1/2 of-wave rectification, we are becoming a kind of full-wave rectification.

Negative Half Wave Rectifier

The above photo indicates you while the diode is off, the terrible 1/2 of the cycle is of the sign flows via the resistor directly to the output, and this is why we are becoming the full-wave rectification just like the output, however, this isn’t the real case.

The output seems like this due to the fact we’ve almost shaped a voltage divider circuit with  9.1K and a 1K resistor, this is why they enter a nice 1/2 of the sign simply was given attenuated.

Half Wave Precision Rectifier Output Waveform

Again, this above photo indicates what occurs after I extrude the weight resistor cost to 220R from 1K.

This isn’t in any respect a trouble that this circuit has.

Undershoot Condition Waveform

How to calculate the output voltage of half wave rectifier
How to calculate the output voltage of half wave rectifier

The above photo indicates an undershoot situation wherein the output of the circuit is going beneath 0 volts and rises after a sure spike.

The above photo indicates an undershoot situation for each of these above-stated circuits, with load and without load. That is due to the fact, on every occasion, the enter sign is going beneath 0, the op-amp is going into the terrible saturation location and the result is the proven photo.

Negative Saturation Region Waveform

Another motive we will say is that on every occasion the enter voltage swings from nice to terrible, it’ll make the effort earlier than the op-amps comments come into play and stabilizes the output, and that is why we are becoming the spikes beneath 0 volts at the output.

This is going on due to the fact I am the usage of a MadPcb jelly bean LM358 op-amp with a low slew rate. You can break out of this trouble, simply via way of means of setting an op-amp with a better slew rate. But hold in thought that this can additionally manifest withinside the better frequency variety of the circuit.

The Modified Precision Rectifier Circuit

The above determination indicates a changed precision rectifier circuit via which we will lessen all of the above-stated flaws and drawbacks. Let’s look at the circuit and determine the way it works.