Electronics > Beginners

TL431 linear power supply

<< < (19/32) > >>

mike_mike:
@spec Thank you.
Can you please replace the transistors that will generate more heat (Q3, Q8) with some transistors that will support more power in order to not heat so much ?

spec:

--- Quote from: mike_mike on December 19, 2018, 09:04:42 am ---@spec Thank you.
Can you please replace the transistors that will generate more heat (Q3, Q8) with some transistors that will support more power in order to not heat so much ?

--- End quote ---
No sweat mike_mike.

I would rather not fit larger transistors because their other characteristics are not so good.  This whole dissipation business for Q3 and Q8 has been blown up out of all proportion (like a lot of things).  Don't even give it a thought. Either transistor type will be fine. :)

iMo:
I would add 4x4n7/100V (4n7-10n) capacitors in parallel with the bridge's diodes, and an 100k (100k-470k) resistor from the RV3's wiper to gnd (in case the wiper looses its contact).

spec:

--- Quote from: imo on December 19, 2018, 09:23:51 am ---I would add 4x4n7/100V (4n7-10n) capacitors in parallel with bridge diodes, and an 100k (100k-470k) resistor from the RV3's wiper to gnd (in case the wiper looses its contact).

--- End quote ---
Thanks. I did consider commutation capacitors across the diodes, but on balance decided to pass, besides which they would mess up my drawing. :D

Good suggestion about the resistor on the wiper. I will embody that. :-+

blackdog:
Hi,

Every time I have to laugh a lot about the standard errors that are made at Linear power supply circuits here on the forum...

Why let's take the last schemes, C8 100uF, and R13 100 Ohm, you must be jokink...

If your reaction is to make the circuit slower because it generates, then you're in a wrong way to solve the problem, YOU NEED SPEED!!!

Every component within de opamp loop creats delay, this delay is your main problem, and also placing extra delay components (C8 and R13) wil make your problems worse.

Extra components in de control loop of a opamp may not create more delay so that the fase margen of de whole circuit comes below 45 degrees.
If you design a goed linear power supply schematic then there wil be 60 a 70 degrees phase margin.

Small tip, place a capacitor over R16 a 240K say 0.1uF.

If you ignore this, you will always start crying.  :box:  :-DD

Kind regards,
Blackdog

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod