Hello,
Trying to change the power supply circuit is based on the following:
But instead of using a zener diode aim to use LEDs.
Edit:
Circuit works.
Trying to change the power supply circuit is based on the following:
An externally hosted image should be here but it was not working when we last tested it.
But instead of using a zener diode aim to use LEDs.
Edit:
Circuit works.
Last edited:
Thanks for the information,
Because of this:
Using 3-pin regulators off-piste: part 1
"For 5V output, a useful substitution is to use two green LEDs in series. These will drop about 1.94v each, or 3.9v across the two, with lower impedance than a 3.9v zener - which makes the output voltage setting more accurate, and with lower noise since the leds are forward-biased PN junctions. You also get bright green light to let you know the reg is working..."
Because of this:
Using 3-pin regulators off-piste: part 1
"For 5V output, a useful substitution is to use two green LEDs in series. These will drop about 1.94v each, or 3.9v across the two, with lower impedance than a 3.9v zener - which makes the output voltage setting more accurate, and with lower noise since the leds are forward-biased PN junctions. You also get bright green light to let you know the reg is working..."
That page was very specifically written (by me) for LM317 and similar adjustable 3-pin regulators.
Your circuit is not comparable; it will need informed revision to use LEDs instead, and infact in the circuit you post using LEDs would offer very minimal gains.
With one additional transistor, you can retain the advantages of a LED, but with added benefits, like much better static and dynamic performance, approximate temperature compensation, flexibility in output voltage setting and low drop-out feature.
Note that a real life circuit will need some kind of start-up method for a deterministic behavior. The exact implementation depends on the context.
Note that a real life circuit will need some kind of start-up method for a deterministic behavior. The exact implementation depends on the context.
Attachments
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
- Home
- Amplifiers
- Power Supplies
- Led + emitter follower regulator