Instead of getting a half-wave rectification, we are getting a sort of full-wave rectification. In my oscilloscope, the yellow signal in the input, and the green signal is the output. The circuit also shows the transfer characteristics of the circuit.īut in a practical circuit, you will not get the output as shown in the above figure, let me tell you why? Now in the above image, you can clearly see what happens when a positive and a negative half cycle of the input signal is applied in the input terminal of the Op-Amp. So, the diode behaves like an ideal diode. That's because we are taking the feedback from the output of the diode and the op-amp compensates for any voltage drop across the diode. The above circuit also shows you the input and output waveform of the precision rectifier circuit, which is exactly equal to the input. To learn how an op-amp works, you can follow this op-amp circuit. The above circuit shows a basic, half-wave precision rectifier circuit with an LM358 Op-Amp and a 1n4148 diode. Now the basics out of the way, let's turn our focus back to the precision rectifier circuit. At this point, the diode will only conduct if the applied input signal is slightly greater than the forward voltage of the diode. In a practical rectifier circuit, the output waveform will be 0.7 volts less than the applied input voltage, and the transfer characteristic will look like the figure shown in the diagram. The above figure shows a practical rectifier circuit with its transfer characteristics. This implies when the input signal is negative, the output will be zero volts and when the input signal is positive the output will follow the input signal. The above figure shows the characteristics of an ideal rectifier circuit with its transfer characteristics. So, without further ado, let's get started.īefore we know about the Precision Rectifier Circuit, let's clarify the basics of the rectifier circuit. Alongside that, I will be discussing some pros and cons of this circuit as well. So, in this tutorial, I am going to show you how you can build, test, apply, and debug a precision rectifier circuit using op-amp. The precision rectifier is another rectifier that converts AC to DC, but in a precision rectifier we use an op-amp to compensate for the voltage drop across the diode, that is why we are not losing the 0.6V or 0.7V voltage drop across the diode, also the circuit can be constructed to have some gain at the output of the amplifier as well. To overcome this issue, the Precision Rectifier Circuit was introduced. We previously explained diode-based half-wave rectifier and full-wave rectifier circuit.
But this rectification method can only be used if the input voltage to the circuit is greater than the forward voltage of the diode which is typically 0.7V. In a typical rectifier circuit, we use diodes to rectify AC to DC. An alternating current always changes its direction over time, but the direct current flows continuously in one direction. A rectifier is a circuit that converts alternating current (AC) to Direct current (DC).