Electronics > Projects, Designs, and Technical Stuff
Simple DIY Linear PSU
panoss:
To change LM317 's Vout I must change R16? Or R17? Or something else?
xavier60:
--- Quote from: panoss on March 15, 2020, 11:50:25 am ---To change LM317 's Vout I must change R16? Or R17? Or something else?
--- End quote ---
Try R17 first. ll try to work it out here.
xavier60:
680Ω for R17 will set it to a bit under 7V.
panoss:
Ok, I did the mods:
R17 = 680Ω
Two 1N4148 in place of D3, voltage across them is 1.22V.
Also I changed Vin to 18V.
RL=no load, Vout=16.93V
RL=20Ω, Vout=14.61V
RL=10Ω, Vout=13.34V
I lowered it to 12V.
RL=no load, Vout=12.04V
RL=20Ω, Vout=11.99V
RL=10Ω, Vout=11.96V
So at lower voltages it 's more stable.
Maybe if I put a second transistor it 'll be more stable at higher voltages?
xavier60:
--- Quote from: panoss on March 15, 2020, 01:02:22 pm ---Ok, I did the mods:
R17 = 680Ω
Two 1N4148 in place of D3, voltage across them is 1.22V.
Also I changed Vin to 18V.
RL=no load, Vout=16.93V
RL=10Ω, Vout=14.61V
RL=20Ω, Vout=13.34V
I lowered it to 12V.
RL=no load, Vout=12.04V
RL=10Ω, Vout=11.99V
RL=20Ω, Vout=11.96V
So at lower voltages it 's more stable.
Maybe if I put a second transistor it 'll be more stable at higher voltages?
--- End quote ---
As the amount of current approaches a transistors maximum rating, the gain usually drops a lot.
What maximum current do you need?
The TIP35C transistors in my bench supply have a combined current rating of 50A to handle 5A. This isn't unusual.
What is Q1's Base voltage with the output voltage set to 9V unloaded?
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version