LT1963 R1 and R2 for 5V

[jimk04]

I have just purchased some more LT1963 regards from Aliexpress ....supposed to be 5v. However they all measure 11.8 or so.
The resistors measure 1.5k and 0.5k.

I have looked at the data sheet but my maths isn't brilliant.

Before I contact the seller I am considering swapping R1 and R2 to give me the voltages I need. To be fair I had considered this before testing them as I may decide to set some up for other voltages anyway. These regs are not as good quality as the 2 I bought off ebay previously but they have larger melf looking resistors so I can attempt to swap. The 'better' boards have 3 x resistors and are tiny smd. But they work at the stated 5v so no need to mess with those.

Can someone help me with the equation please to give me R1 and R2 for 5v and maybe 8v.

Vout = 1.21(1+r2/r1)+(Iadj)R2

Where Iadj is 3uA at 25degrees.....

As far as inputting into a calculator...is the 3uA = 0.003?

Thanks very much.

 

[Ketje]

Take R2=510Ω (upper one) and R1=1k6 (lower one)
And yes, 1mA=1000µA
Mona

 

[jimk04]

Thankyou for that

So with my measured 1.5k and 0.5k I should be getting somewhere near 5v then....hmm.

 

[CallMeMike]

Take R2=510Ω (upper one) and R1=1k6 (lower one)
And yes, 1mA=1000µA
Mona

... so 3 uA = 0.000003 A
This is assuming that 'uA' meant 'microAmperes' ... Guilty, I'm using the same connotation (actually we should use the Greek letter used by @Ketje but looking for the combination of keyboard keys for the right character is such a chore )

 

[sgrossklass]

Somewhat surprisingly, it seems like you guys in the UK do not commonly have access to µ, at least the Windows users - a lot of other layouts feature it on AltGr+M, including US International, and similarly so the Linux layouts UK Extended and UK International. Ah, it looks like a few people have made UK International layouts using MSKLC - I suggest picking up one of these.
UK International (United Kingdom International) keyboard -- zolid.com
UK International Keyboard Layout

Those regulators look suspect. I would check to see whether the layout is actually correct. If that checks out - does anyone make a plain fixed +12V reg in the same package? Could be something else altogether, with counterfeit chips you never know.

 

[Ketje]

... so 3 uA = 0.000003 A
This is assuming that 'uA' meant 'microAmperes' ... Guilty, I'm using the same connotation (actually we should use the Greek letter used by @Ketje but looking for the combination of keyboard keys for the right character is such a chore )

If the µ is allready somewhere in the text, just copy-paste it
Mona

 

[RJM1]

ALT codes
Alt Codes List of Alt Key Codes Symbols
To type "µ" hold down the "alt" key and type "230"

 

[jimk04]

Thanks for the keyboard lesson

So seems these are dud. They dont regulate at all. Just get a small V drop between in and out.

Dispute time!

 

[ubergeeknz]

Can you share a URL for what you bought?

 

[jimk04]

These are the bad ones. And they dont look as nice first hand.
￡9.20 | 5pcs LT1963 LT1963EQ Power Converter 12V to 5V DC to DC Power Supply module 5V Fixed Output Replace LM1085 108X series
AliExpress

These were the good ones and are far cleaner and nicer boards

LT1963 - 7805 Converter / Power Module Conversion 5.5 - 12V to 5V; 1.5A 310333109555 | eBay

 

[CallMeMike]

If the µ is allready somewhere in the text, just copy-paste it
Mona

Don't you think that I've passed such a good opportunity...! -) I've saved it safely alongside Beta, Lambda, Ro, Sigma and other Hellenic letters (I'll start promoting them to friends & family as good names for house pets...)

 

[Ketje]

Don't you think that I've passed such a good opportunity...! -) I've saved it safely alongside Beta, Lambda, Ro, Sigma and other Hellenic letters (I'll start promoting them to friends & family as good names for house pets...)

Here some more for your collection
π Ω √ x² x³ ¼ ½ ¾ ♫ ♪ Ⅻ ⑫ ± ≤ ≥ ㉫ ᕫ ™ ᵫ ൫ © ® † ‰ 
≡ ≢ « » ≧ ≦ ≫ ୫ ౫ ʘ Ø °C �ß zł ∞ 
Mona

 

[MagicBus]

Α Β Γ Δ Ε Ζ Η Θ Ι Κ Λ Μ Ν Ξ Ο Π Ρ Σ Τ Υ Φ Χ Ψ Ω


α β γ δ ε ζ η θ ι κ λ μ ν ξ ο π ρ σ (ς) τ υ φ χ ψ ω

 

[CallMeMike]

Introduction to Greek language (highjacked... used to be 'LT1963 R1 and R2 for 5V')

Α Β Γ Δ Ε Ζ Η Θ Ι Κ Λ Μ Ν Ξ Ο Π Ρ Σ Τ Υ Φ Χ Ψ Ω


α β γ δ ε ζ η θ ι κ λ μ ν ξ ο π ρ σ (ς) τ υ φ χ ψ ω

I hope that @jim04 will forgive us... at the end of the day I guess that this info will be handy to many...

 

[MagicBus]

Apologies to @jim04! Seems the thread moved naturally since he got his answers. Just one more line to say that in windows there are lots of language packs to download and switch them in your keyboard at will. In my case shift+alt to switch between English and Greek.