Diode Output

rspuzio

Joined Jan 19, 2009
77
You have a 3 V battery. The diode has a potential drop
of around 0.7 V. 3 - 0.7 = 2.3 Hence, the diode turns
on at 2.3 V (in your case -2.3 because of the direction in
which you hooked up the diode and the battery), which is
just what you see in your plot.
 

ELECTRONERD

Joined May 26, 2009
1,147
In power supplies, diodes are used to rectify an AC output. A diode lets current flow one direction but not the other. As an example, look at the picture I have on my oscilloscope. In the first picture, you'll notice just a standard sine wave. Next, I have a diode with the cathode to the negative ternimal. Lastly, I have the cathode to the positive ternimal which chopped off the positive AC. If we were to put a capacitor it would charge from the peak of the cycles and discharge on the 0V. This leaves a steady DC output, although there will still be some ripple.

If you switched the diode to the opposite polarity the waveform would flip upside down.
 

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BillB3857

Joined Feb 28, 2009
2,570
Thank you guys for answering me
I understood the 2.3 volt part :)
but how the voltage increase to 10 volt , That i dont understand
The -10 volts you see is due to the fact that during that period, the diode is reverse biased; therefore no current flow (except into the measuring device) and no voltage drop through the current limiting resistor. During the positive half cycle of your source, the diode is forward biased and is allowing current flow into the battery. The remainder of the positive 10 volt half cycle is dropped across the current limit resistor. Hope this helps.
 

Thread Starter

Computer Engineer

Joined Aug 25, 2009
7
The -10 volts you see is due to the fact that during that period, the diode is reverse biased; therefore no current flow (except into the measuring device) and no voltage drop through the current limiting resistor. During the positive half cycle of your source, the diode is forward biased and is allowing current flow into the battery. The remainder of the positive 10 volt half cycle is dropped across the current limit resistor. Hope this helps.
very helpful thank you:D
 
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