# Half wave rectifier

#### MrChips

Joined Oct 2, 2009
26,133
I don't understand were you get any values from to work out the average.

Yes I can do Calculus.
What parameters are required in order to describe a sine wave?

#### Pickles

Joined Mar 13, 2015
29
I would recommend LTSpice but the learning curve is steep. I think it would distract from the problem at hand. Doesn't your school use a software tool such as Multisim?

https://www.analog.com/en/design-center/design-tools-and-calculators/ltspice-simulator.html#

You get the values from the trace and the given parameter for the circuit.
Yes they told me to use Multism but I am waiting for the tutor to come back to me with activation codes etc, as they aren't working.

I just want to try and get these questions answered when I am off work for the weekend as during the week I don't get much time to do it.

#### Pickles

Joined Mar 13, 2015
29
What parameters are required in order to describe a sine wave?
Amplitude, cycles, frequency, peak to peak and RMS?

#### MrChips

Joined Oct 2, 2009
26,133
Amplitude, cycles, frequency, peak to peak and RMS?
You only need two. The rest are redundant. (Sometimes you need phase angle but this is unimportant in your case.)
(You may also need DC offset. But let's ignore that too.)
Let's cut to the chase (to avoid playing the game of 101 Q & A).
All you need is amplitude and frequency.
You can derive RMS and peak-to-peak from amplitude.
Which of the three values, amplitude, RMS, peak-to-peak do you know for both input and output waveforms?

#### Pickles

Joined Mar 13, 2015
29
You only need two. The rest are redundant. (Sometimes you need phase angle but this is unimportant in your case.)
(You may also need DC offset. But let's ignore that too.)
Let's cut the chase (to avoid playing the game of 101 Q & A).
All you need is amplitude and frequency.
You can derive RMS and peak-to-peak from amplitude.
Which of the three values, amplitude, RMS, peak-to-peak do you know for both input and output waveforms?
The only figures I can see on the diagram is 5 V pk and 1KHz.

#### WBahn

Joined Mar 31, 2012
26,398
Ok thanks everyone. To work out the average value of the input and output signal would you use this equation...

View attachment 200318

Many thanks
Where did that equation come from?

How does it apply to the input signal?

How does it take into account the effect of the voltage dropped across the diode?

#### WBahn

Joined Mar 31, 2012
26,398
I don't understand were you get any values from to work out the average.

Yes I can do Calculus.
What is the input voltage as a function of time. Assume that the waveform is at 0 V at t=0.

What is the output voltage as a function of time if you assume that the voltage drop across the diode is 0 V when forward biased?

What is the output voltage as a function of time if you assume that the voltage drop across the diode is 0.7 V when forward biased?

If you know v(t) and that it is periodic with period T, how do you find the average value of v(t)?

#### MrChips

Joined Oct 2, 2009
26,133
The only figures I can see on the diagram is 5 V pk and 1KHz.
For a sine wave symmetrical about 0V the peak voltage is the same as its amplitude.
Intuitively, what is the average value of such a sine wave of 5V amplitude.

#### Pickles

Joined Mar 13, 2015
29
For a sine wave symmetrical about 0V the peak voltage is the same as its amplitude.
Intuitively, what is the average value of such a sine wave of 5V amplitude.
So if the voltage is the same as the amplitude then it will be 5?

#### MisterBill2

Joined Jan 23, 2018
11,913
So if the voltage is the same as the amplitude then it will be 5?
If the peak to peak voltage is ten volts, then the peak voltage will be 5 volts, the average will be less, likewise the RMS value and the DC equivalent is someplace in between.

#### MrChips

Joined Oct 2, 2009
26,133
So if the voltage is the same as the amplitude then it will be 5?
Try again.
Take 10 samples of the wave, sum them, and divide by 10.