Diodes and LEDs Flashcards
the current through a resistor is _______________ to the potential difference (at constant temperature)
b
when is the current through a resistor directly proportionate to the potential difference ?
at a constant temperature
The current through a _______ is not directly proportional to the potential difference
why?
the current through a filament lamp is NOT directly proportional to the potential difference
because the filament gets hot so the resistance increases
WHATS THE SYMBOL FOR A DIODE?
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what is the function/key feature of a diode?
why?
diode allows current flow in one direction only
diode has a very high resistance in the reverse direction
what does the arrow in a diode show us
shows us the direction the conventional current must flow in
in a circuit the diode is pointing to the right
the conventional current is flowing from right to left
what happens to the current in the diode?
why does this happen?
the diode will not allow the current to pass through
the diode has a very high resistance in the reverse direction
what side does the conventional current flow from and to?
what side does the electron current flow from and to?
conventional current - conventional current flows from the positive side of a cell to the negative
electron current - electrons flow from the negative side
looking at the current potential difference graph for a diode, we can see that no current can flow in the ______ direction
however in the _____ direction,
what increases as the _____ increases?
looking at the current potential difference graph for a diode, we can see that no current can flow in the reverse direction
however in the forward direction,
current increases as the potential difference increases?
what are diodes extremely useful for?
controlling the flow of current in circuits
what is the symbol for an LED?
same as diode but with arrows coming of it
what is an LED?
how is an LED similar to a diode
how is an LED different to a diode?
an extremely energy-efficient source of light
like a normal diode, only allows current to flow in the forward direction
however unlike a normal diode, an LED gives off LIGHT when a current flows through
what does an LED do when a current flows through?
gives off light
