# Power regulators



## Deperduci (Jul 31, 2022)

My apologies if the wrong sub section but what equivalent chips exist to https://www.mouser.com/ProductDetail/Texas-Instruments/LM2940CT-15-NOPB?qs=X1J7HmVL2ZG1l9S5UEMUVA== ? Mouser says a year out, Tayda peed it's pants laughing when I tried searching.. 
it's for a solid state power board/quasi headphone amp. 12 v supply the BOM says can chintz using a 7818 but says the lm2940 for 9v supply to stabilize it's output doubler. 

Or does anybody even have 1 of those laying in a box? or should I just saccrifice an after market 12v pdeal/pc supply 😉


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## Betty Wont (Jul 31, 2022)

L7815CV L7815 7815 Voltage Regulator IC +15V 1.5A
					

SGS THOMSON - Get It Fast - Same Day Shipping




					www.taydaelectronics.com
				



Maybe this one?


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## benny_profane (Jul 31, 2022)

Betty Wont said:


> L7815CV L7815 7815 Voltage Regulator IC +15V 1.5A
> 
> 
> SGS THOMSON - Get It Fast - Same Day Shipping
> ...


It’s not an LDO, but if you’re feeding it 18V, you shouldn’t have a problem. 

I’m really confused. You’ve mentioned 12V, 15V (i.e., the LM2940), and 18V regulators. Do you need all three?


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## fig (Jul 31, 2022)

Can you post the BOM?


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## Deperduci (Jul 31, 2022)

This board here.  and it's pdf BOM here if I can get away with the LM78xx series I will. It blows nonkey duts that was the last the shop had for a bit, I like finding these min amp projects.

see if the formatting stays with a Bill of materials Device# Qty Value Comment
 Resistors 
R1 1 2M2
 R2 1 330k
 R3 1 6k8 Test with LED first for brightness
 R4 1 220R
 R5 1 2R2
R6 1 47R 
R7 1 1R- 1W Capacitors 
C1 1 10n box film
 C2 C6,C11 3 100n box film
 C4,C5,C8 3 2200u/40V polarized electro (max. 12mm Ø)
 C7,C3 1 100u/25V polarized electro (max. 5mm Ø)
 C9 1 470u/25V polarized electro (max. 8mm Ø)
 C10 1 47n box film C12 1 10u polarized electro
 Diodes
 D1,D2 2 1N5817
 D3 1 LED
 ICs
 IC1,IC2 2 TDA 2003
 IC3* 1 LM2940CT-15 (9V supply) uA 7818 (12V supply) The 15V LDO version is available from mouser P# LM2940-15/NOPB 
Other Heatsink** 1 anything that fits the three TO220 ICs on one piece. Running without heatsink will destroy one or more ICs! 
*If you run this with a 12V wall mart you can use a 7818 voltage regulator. If running from a 9V supply you need the LM2940-15/NOPB regulator which successfully can stabilizee the approx. 16V coming from the voltage doubler in front. A normal 7815 will not be sufficient!


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## Deperduci (Jul 31, 2022)

Now you see why I was digging as I make out the mail order for the parts I don't have  by the box, like the voltage regulator and the 2200uf caps I want to feed this thing wired direct~ish from Black_eye or Space heater from Sushi Box to make a poor and old fart's JTM 45. As I said I might just locate a 12 volter to dedicated(hardwire through a fuse) and us the lm78xx since most places have those in stock.


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## fig (Jul 31, 2022)

I have one on the way for you.


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## Deperduci (Jul 31, 2022)

I hope it's the regulator which you didn't have to do, because I don't think I've ever seen a 12 volt Walmart or is that part of the company attempting to go green using a solar charged battery array for the stores...


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## fig (Jul 31, 2022)

Deperduci said:


> I hope it's the regulator which you didn't have to do, because I don't think I've ever seen a 12 volt Walmart or is that part of the company attempting to go green using a solar charged battery array for the stores...


It’s an LM2940-15 . If it checks out, I’ll mail it to you. Then you can use a normal 9v according to the doc.


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## Deperduci (Aug 1, 2022)

where did you find it? the box of bread board or a vendor I have yet to locate?


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## giovanni (Aug 1, 2022)

Fig has a deep stash…


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## Deperduci (Aug 1, 2022)

That would mean it's more a donut than cookie duster. (if my threads get derailed, I make sure it's out by a field and not downtown   )
Why I thought it was from the box of breadboard, something he cooked up and then decided that expense or specifics  weren't as needed. TheLM2940 is about 6x the price of using something from the LM78XX group.


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## fig (Aug 2, 2022)

It’s should be here tomorrow, maybe next day.


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## Deperduci (Aug 2, 2022)

@fig I might have the solution because I do have enough cranial flatulance to live down to my screen name


fig said:


> It’s should be here tomorrow, maybe next day.


The PSU I have on the 5 watt headphone I got from the man downunda is already a 12v 1.5amp with 3.5 mm jack , I just have to watch the power jack,  being center post positive as opposed to center ground like most of us build for. 🤦‍♂️ 🤬🤦‍♂️

Benny, Betty, those might work but I'll get the 18v version, I need to put together a tayda order for my 2 sushi box boards anyways and just say fudge it with a linear pot for this other project I got from Israel..


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## fig (Aug 3, 2022)

Deperduci said:


> @fig I might have the solution because I do have enough cranial flatulance to live down to my screen name
> 
> The PSU I have on the 5 watt headphone I got from the man downunda is already a 12v 1.5amp with 3.5 mm jack , I just have to watch the power jack,  being center post positive as opposed to center ground like most of us build for. 🤦‍♂️ 🤬🤦‍♂️
> 
> Benny, Betty, those might work but I'll get the 18v version, I need to put together a tayda order for my 2 sushi box boards anyways and just say fudge it with a linear pot for this other project I got from Israel..


Well, if you decide you want it, I’ll send it to you...it was well-packaged and shipped quickly…







I tested it and it functioned as expected per the datasheet example.


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## Deperduci (Aug 4, 2022)

I might take it anyways and send you some excess 4049/4069 chips I acquired when I misordered for a flanger board. I have to check the sheets while i have the 12v PSU, not sure if the sushi box board is also 12v compliant or safe to just add a couple resistors to the 12v patch to make it 9. Where did you even find it?


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## fig (Aug 4, 2022)

ebay.

I’ve a feeling that the L78 would work, but I wouldn’t suggest using it without trying it myself first. If you’ll DM your address, I’ll get this in the mail. 

Edit: Just ask Nathan about his board. It may have some special current requirements. 🤷‍♂️


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## Deperduci (Aug 4, 2022)

DM sent. I'll let Nate get a nap before I ask...I still have to juggle using a larger box like a 1590c/j or making something from both angle and sheet aluminum to hold it all.


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## danfrank (Oct 5, 2022)

FYI, the LM2937 is the same as a LM2940 reg (LDO) but only good for up to 500ma:



			https://www.mouser.com/ProductDetail/Texas-Instruments/LM2937ET-15-NOPB?qs=X1J7HmVL2ZEWqTJ5%252BIk1bA%3D%3D&gclid=EAIaIQobChMIl-3mtMXJ-gIVmRXUAR022AgkEAAYASAAEgKcIvD_BwE


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## Deperduci (Oct 5, 2022)

the project got put on the back burner but the amp had a bit higher draw, min 1 ampere so that regulator would likely burn out quick.


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