voltage drop

[blessbernie]

after putting my PIC in d socket, d voltage from the 7805 drops to abt 1.4v. wat could be the cause. urgent plz. it's jst a simple temperature sensor circuit

 

[crutschow]

Something is drawing more current than the supply can deliver.

 

[blessbernie]

hw can I figure that out.

 

[alec_t]

Carefully examine your circuit to see if there are any stray wire strands or solder splashes causing a short-circuit somewhere.
Double-check the circuit you have built, to ensure it's consistent with the schematic.

 

[spec]

Or the 7805 could be misbehaving- perhaps oscillating. Have you got any decoupling capacitors across the supply lines. If not try 100nF.

spec

 

[blessbernie]

tnx alot Alec_t and spec

 

[ronsimpson]

d voltage from the 7805 drops to abt 1.4v

What is the input voltage at the 7805?

 

[MikeMl]

Read Post #14 in this recent forum thread It deals with not having sufficient voltage upstream of the regulator...

 

[Nigel Goodwin]

I would strongly suspect you've put the chip in the wrong way round!

This would produce exactly what you're getting - the chip will also be getting red hot, so don't touch it.