Question

The current flowing into the collector lead of a certain bipolar junction transistor (BJT) is measured to be 1 nA. If no charge was transferred in or out of the collector lead prior to t = 0, and the current flows for 1 min. calculate the total charge which crosses into the collector.

Answer 1

Answer:

the total charge which crosses into the collector is 60 nC

Explanation:

Given the data in the question;

current flowing into the collector lead of the bipolar junction transistor (BJT); i = 1 nA = 10⁻⁹ A

no charge was transferred in or out of the collector lead prior to t = 0

the current flow time t = 1 min = 60 sec

Now we write the relation between current, charge, and time;

i = dq / dt

where i is current, q is charge and t is time. { d refers to change }

Now,

$q=\int\limits^t_{t=0} {i(t)} \, dt$

$q=\int\limits^{t=60}_{t=0} { (10^{-9}) } \, dt$

$q = ( 10^{-9}) (t)_0^{60$

$q = ( 10^{-9}) ( 60 - 0 )$

q = 60 × 10⁻⁹ C

q = 60 nC

Therefore, the total charge which crosses into the collector is 60 nC