W
wylbur37
- Jan 1, 1970
- 0
When using an LED from a power source whose voltage is higher than the
rating of the LED, a resistor is typically used.
If more than one LED is to be used (let's say three),
each one would have its own respective resistor,
and the schematic would look something like this ...
+----------+-----------+-----------+--------------
| | | |
| | | |
| LED-1 LED-2 LED-3
power | | |
source | | |
| resistor-1 resistor-2 resistor-3
| | | |
| | | |
+----------+-----------+-----------+--------------
But if all the LEDs were of the same voltage and amperage
(e.g., if they were all of the typical 3.6V 20mA),
isn't there a simpler way to do this by using only ONE resistor?
In other words, can't it be done like the following ?
+--------------+-----------+-----------+---
| | | |
| | | |
power LED-1 LED-2 LED-3
source | | |
| | | |
| | | |
+---resistor---+-----------+-----------+---
And what would be the proper value of the resistor?
(I'm guessing it would be one third of what it was in the first diagram
because the required voltage reduction would be the same but the
effective current draw of the 3-LED assembly would be three times what it
was before.
So if the power source were 6V and the LEDs were 3.6V and 20mA each,
then the required resistance would be 120 ohms in the first case
and 40 ohms in the second case. Correct?)
rating of the LED, a resistor is typically used.
If more than one LED is to be used (let's say three),
each one would have its own respective resistor,
and the schematic would look something like this ...
+----------+-----------+-----------+--------------
| | | |
| | | |
| LED-1 LED-2 LED-3
power | | |
source | | |
| resistor-1 resistor-2 resistor-3
| | | |
| | | |
+----------+-----------+-----------+--------------
But if all the LEDs were of the same voltage and amperage
(e.g., if they were all of the typical 3.6V 20mA),
isn't there a simpler way to do this by using only ONE resistor?
In other words, can't it be done like the following ?
+--------------+-----------+-----------+---
| | | |
| | | |
power LED-1 LED-2 LED-3
source | | |
| | | |
| | | |
+---resistor---+-----------+-----------+---
And what would be the proper value of the resistor?
(I'm guessing it would be one third of what it was in the first diagram
because the required voltage reduction would be the same but the
effective current draw of the 3-LED assembly would be three times what it
was before.
So if the power source were 6V and the LEDs were 3.6V and 20mA each,
then the required resistance would be 120 ohms in the first case
and 40 ohms in the second case. Correct?)