The Voltage Regulator 78xx
The 78xx is a widely used voltage regulator.
It is designed as a fixed voltage regulator,
is cost effective, robust and widespread.
Originally called LM78xx,
today many copies are available as L78xx, ?78xx, etc.
Therefore, they are generally referred to as 78xx.
The last two digits indicate the voltage
for which the voltage regulator is designed...
-
The 7805 regulates the output voltage to 5V,
-
The 7809 regulates to 9V, etc.
A voltage regulator 78xx.
(Enlarge)
|
Circuit symbol voltage regulator 78xx.
The 78xx comes in a TO220 casing with three
connectors...
| Pin |
Symbol |
Description |
Value |
| 1 |
Vin |
Input voltage |
Max. 35 V |
| 2 |
GND |
Ground |
0 V |
| 3 |
Vout |
Output voltage |
5 V (7805)
9 V (7809) |
|
The standard 78xx has a
maximum current of 1A, although there are
variations...
-
The 78Lxx has a maximum current of 100mA,
-
The 78Mxx has a maximum current of 500mA.
In addition, the 78xx is protected against short circuit and
overheating.
In the following experiments you use the
standard 7805 and 7809...
