7805

High current regulator

How to get past the current limit of a 7805 regulator by adding a PNP pass transistor. Resistor Re, together with the MJ2955's VBE, sets when the transistor steps in to share the current, taking the output up to about 5 A.

linear regulator
high current
pass transistor
MJ2955
78xx

7805Power

Constant current source

How to use a 7805 voltage regulator as a constant current source. A single resistor sets the output current at I = 5 V / R, taking advantage of the fixed 5 V the regulator keeps between its output and common pins.

linear regulator
current source
constant current
TO-220
78xx