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What's the differences in 7805 voltage regulators?

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KevinAlaska

New Member
Are all voltage regulators that have the 7805 the same besides the amp rating?
I have seen an LM7805C & L7805CV. What's the difference?
I guess there are different shapes to suit different mounting needs. Different max voltage inputs and different max currents. But does 7805 mean what?

I hope this makes sense.

Kind Regards

Kevin
 

Externet

Active Member
7805 means the original manufacturer part numbering. 78xx series, 5V output.
The current rating on 78xx regulators is not the suffix.
'Low' current are 78L05,
'Medium' current are 78M05,
'Typical 1A' are 7805,
'High' current are 78T05

Other voltages as 12v are
78L12, 78M12, 7812, 78T12...
 
Last edited:
A

amando96

Guest
78 means positive voltage, and 05 means the output is +5v

7805 - positive 5v output, 1 amp
7905 - negative 5v output 1 amp

78M05 - positive 5v output 0.5 amp
78L05 - positive 5v output 0.1 amp
 

KevinAlaska

New Member
Wow. Very awesome. Thank you very much. After reading all the posts I feel I now have a strong view of what I needed.

My thanks to everyone,

kind regards

Kevin
 

patcou

New Member
The letters before the part number indicate the manufacturer:
LM78xx - Made by or for Texas Instruments (formerly National Semiconductor, bought by TI in September 2011)
L78xx - STMicroelectronics
TS78xx - Taiwan Semiconductor
MC78xx - Motorola (now ON Semicondutor - the Semiconductor Components Group of Motorola was sold off in 1999)


Other trivia:
- LM340A-x.x is the same as the LM78XX. So, LM340A-5.0 = LM7805.
- LM317 is an adjustable output linear regulator with 1.5A output - needs 2 additional resistors to define the output voltage.
- 79xx are complementary negative voltage regulators.
- To get even more current out of these regulators, a properly rated resistor can be connected from the input to the output, although this degrades the regulation performance.
- Fairchild made a part called the LM78S40 that is not a linear regulator but a switching regulator. (Fairchild was sold to National Semiconductor in 1987 - maybe that's why they used the LM prefix?)
 

ronsimpson

Well-Known Member
Most Helpful Member
A LM7805 is an exact copy no matter where it comes from. Some companies will not buy a part unless there is more than one source. It is common for companies to share their silicon.
If Ron Simpson makes a copy that is close but not exact (using different silicon) it might be RS7805. It might be better, or a little worse.
 

Reloadron

Well-Known Member
Most Helpful Member
The 7805 regulator was about 8 years newer when the thread began. :)

Ron
 

Reloadron

Well-Known Member
Most Helpful Member
The 7805 is timeless. The 7805 is ETERNAL.
I like to think so since I have a pile of them looking for an application. :)

Ron
 

ChrisP58

Well-Known Member
-
-
- Fairchild made a part called the LM78S40 that is not a linear regulator but a switching regulator. (Fairchild was sold to National Semiconductor in 1987 - maybe that's why they used the LM prefix?)
Fairchild became an independent company again in 1997. In Sept 2016, they were bought by ON Semiconductor.
National Semiconductor was bought by Texas Instrument in Sept, 2011.
 

Ian Rogers

User Extraordinaire
Forum Supporter
Most Helpful Member
Fairchild became an independent company again in 1997. In Sept 2016, they were bought by ON Semiconductor.
National Semiconductor was bought by Texas Instrument in Sept, 2011.
And this is an 8 year old revived thread....
 

unclejed613

Well-Known Member
Most Helpful Member
maybe that's why they used the LM prefix?
actually "LM" was the prefix for National Semiconductor linear chips. IIRC, it meant "Linear Microcircuit", later they came out with a line of FET input op amps, and used "LF" for the prefix. Fairchild linear chips used a "uA" (the "u" being a "mu") with the meaning of "micro Analog". TI's prefix was "TL" for "TI Linear".
 

schmitt trigger

Well-Known Member
Another necro-thread.
But as relevant today, as it was perhaps 30 years ago.

I've a saying: if you haven't used at least once a 7805 in one of your projects, you really are not an electronics enthusiast.
 

OlPhart

Member
The 78xx / 79xx / 78Lxx and 79Lxx series are the cornflakes of dealing with power.
Akin to the venerable 555 for time based stuff.
 

dknguyen

Well-Known Member
Most Helpful Member
Another necro-thread.
But as relevant today, as it was perhaps 30 years ago.

I've a saying: if you haven't used at least once a 7805 in one of your projects, you really are not an electronics enthusiast.
Haha, I never have because I always end up picking and buying another kind.
 
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