Is there a difference between a 7805 regulator and a LM7805?

The short answer is, "no".  These are essentially the same part. The  5 volt version of the 78-series linear voltage regulators in a T0-220 package.  Predictably, the one sold by RadioShack(r)  is priced higher.

If you are wondering what the "LM" stands for, I think it is a prefix belonging to a particular manufacturer.  The confusing thing is that I think I have seen more than one manufacturer making the same chip starting with "LM".  The links below might, or might not, offer some clues to the mysterious "manufacturer's prefix".

juniortan2 years ago

They are both kinda similar, except that the 7805 is spec'd for 1.5A and LM7805 for 1A nominal output

nannasin284 years ago

TheLM7805series of three terminal positive regulators are available in the TO-220 package and with several fixed output voltages, making them useful in a wide range of applications. Each type employs internal current limiting, thermal shut down and safe operating area protection, making it essentially indestructible. If adequate heat sinking is provided, they can deliver over 1A output current. Although designed primarily as fixed voltage regulators, these devices can be used with external components to obtain adjustable voltages and currents.