Menticol
Active Member
Hi!
I got this schematic from an old textbook, a variable votage regulator with passing transistor, to handle more current. Nothing special for all of you.
**broken link removed**
I want to use the same transistor trick, on a fixed voltage PSU to power my boombox from a car battery. The requeriments are
+ 5V
0V
-5V
At 3 amps peak, 2 nominal
As far as my novice knowedge can see, the 0,6 ohm resistor (let's call it R1) triggers the transistor when too much current is beign drawn from the regulator.
So, three novice questions:
Can I replace the MJ2955 transistor with any other power NPN?
What should be the value of R1 if a LM7805 regulator is used? (I think it's determined by R = Operating Voltage / Maximum Regulator Current but I'm not sure)
Can I use the same transistor trick with a LM7905? (most critical question)
Thank you so much in advance
I got this schematic from an old textbook, a variable votage regulator with passing transistor, to handle more current. Nothing special for all of you.
**broken link removed**
I want to use the same transistor trick, on a fixed voltage PSU to power my boombox from a car battery. The requeriments are
+ 5V
0V
-5V
At 3 amps peak, 2 nominal
As far as my novice knowedge can see, the 0,6 ohm resistor (let's call it R1) triggers the transistor when too much current is beign drawn from the regulator.
So, three novice questions:
Can I replace the MJ2955 transistor with any other power NPN?
What should be the value of R1 if a LM7805 regulator is used? (I think it's determined by R = Operating Voltage / Maximum Regulator Current but I'm not sure)
Can I use the same transistor trick with a LM7905? (most critical question)
Thank you so much in advance
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