# Maximum voltage of battery when a diode is attached to it

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In an ideal p-n junction diode can withstand currents up to 10mA under forward bias. The diode has a potential difference of 0.5V across it which is assumed to be independent of current. What is maximum voltage of battery used to forward bias the diode when resistance of 200Ω‎ is connected in series with it.

I understand that I should apply $V = IR$ to this scenario but I'm not sure how to apply this with the diode?

edited Nov 4, 2016
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Thanks for your question Junaid and welcome to the site :-)

1 vote

Let $V$ be the voltage of the battery.

The voltage over the diode is given to be $0.5$ and therefore the voltage over the resistor is given by $V - 0.5$.

Using $V = IR$ we can compute the current over the resistor,

$I = \frac{V}{R} = \frac{V-0.5}{200}$

Since the maximum current in the circuit is $0.01A$, we can find the maximum voltage of the battery by solving the equation,

$0.01 = \frac{V-0.5}{200}$

Therefore,

$V = 2.5$ Volts

answered Nov 4, 2016 by (1,486 points)
selected Nov 4, 2016