Looking for data about the LT8001P

Discussion in 'Radio Circuits, Repair & Performance' started by KK6VQK, Jul 20, 2019.

ad: L-HROutlet
ad: l-rl
ad: Subscribe
ad: L-MFJ
ad: MessiPaoloni-1
ad: Left-3
ad: K5AB-Elect-1
ad: Left-2
  1. KK6VQK

    KK6VQK Ham Member QRZ Page

    hi!

    I'm servicing a newly-acquired old TS-940S and it's in .. well, it's working now. However, I noticed that the LT8001P diodes give off a red glow. Using google shows this is apparently normal - I'm guessing they're being used as a larger voltage drop diode of some sort but I can't find any datasheets online for this part.

    Does anyone happen to know what the specs are on this diode?

    Thanks!


    -adrian
    (kk6vqk)
     
  2. G4COE

    G4COE Ham Member QRZ Page

    I don't know where you mean.... but

    if you look at the 'Auto tune' schematic you'll find three or four regulator IC's.... and there's one used in each earth lead from the regulators, a diode would typically have a 0.7V drop across it, obvioulsy a LED would have some 2 volts or so drop.... so far so good. You'll find em' on page 99 I think, near the bottom centre of the page.

    Lets say we have a 6V regulator if instead of grounding the negative lead and insert a diode we'll have 6V + 0.7V thus the output woud be raise to 6.7V

    A led or zener diode would do the same job, in 'our' case they use a LED, now I don't know the specs of these LT8001P LED's so for explanation we'll assume they need 2V to make em' light, if we use one of these the output will be 8V (6V +2V).

    They are simply use to 'lift' the regulated voltage.... if you KNOW the regulator type number, simply measure the regulator output and you'll find it has been raised by the LED.... this voltage difference would be the same for all these LT8001P diodes.

    Dave.
     

Share This Page