I am new to LDO (Low Voltage Regulator) world.
I'm curious what you people had buy and have in your personal stock at home.
(also what packages, TO-220 SOT-223)
From the good old Ebay I spot a couple and also open their respective dataSheets:

LM317T (LM117,LM217) Input Voltage : 2-40V
OUTPUT CURRENT Maximum Load Current 2.2A
OUTPUT VOLTAGES adjustable over a 1.2 to 37V range.

L7800 SERIES
Input Voltage : 2-35V (5-18); 20-40V (20-24)
OUTPUT CURRENT 1.5A
OUTPUT VOLTAGES 5; 5.2; 6; 8; 8.5; 9; 10; 12; 15; 18; 24V

AMS1117 - 1.2V 1.5V, 1.8V, 2.5V, 2.85V, 3.3V and 5.0V (Advanced Monolithic Systems)
Input Voltage : 2-18or30V Output Current of 800mA
OUTPUT VOLTAGES 1.5V, 1.8V, 2.5V, 2.85V, 3.3V and 5.0V

HT73xx-7 Input Voltage :
2-30V output current : 250mA
OUTPUT VOLTAGES: 2.1, 2.3, 2.5, 2.7, 3.0, 3.3, 3.6, 4.0, 4.4, 5.0

HT75xx-1
Input Voltage : 24V
output current : 100mA
OUTPUT VOLTAGES: 2.1, 2.3, 2.5, 2.7, 3.0, 3.3, 3.6, 4.0, 4.4, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 12.0

 

LM317 for those times I need to play around and L78xx for fixed. But I'm sure there are better solutions. At least the old devices are cheap.
Here is a cut and paste from my stock list:
L7805CV VOLTAGE REGULATOR 5V POSITIVE
L7808CV VOLTAGE REGULATOR 8V POSITIVE
L7905CV VOLTAGE REGULATOR -5V NEGATIVE
LM317T VOLTAGE REGULATOR 1.5A, 1.2V TO 37V ADJUSTABLE
LM340T5 VOLTAGE REGULATOR 5V
LM340T12 VOLTAGE REGULATOR 12V
LT1083CT VOLTAGE REGULATOR 3A, 5A, 7.5A Low Dropout Positive

What I have on hand in TO-220...

 

LDO stands for Low Dropout Regulator.
It allows for a smaller difference between the input voltge and the maximum regulator output voltage.
They typically have a minimum dropout voltage of a volt or so, compared to the 2-3V for the old LM317.

 

Thank you very much mister SamR. It will help me to choose better when i can reference to your colection.

 

LDO stands for Low Dropout Regulator...

You are right mister crutschow . Why in the hell i did that mistake? I suppose I unintentionally shortcut it without thinking; "LOW DROPOUT VOLTAGE REGULATOR". Definitely my mistake here. As I said, i am a bit new to these devices. It turns out they are complex circuits inside, i just seen a DIE (close up inside the CHIP) from Wikipedia. Fantastic.
Can you illuminate me about 1 aspect?
I just play with a [resistor Voltage Divider], made from 2 resistors. It is linear increasing the voltage divided as I increase the source voltage.
Then i play with a [zenner diode shunt regulator], very interesting circuit, but in reality, it really does what the resistor V divider does. I was expecting it to 'clamp' to my Zener value. It just goes with the flow.
And then i look all day over these LDO (low dropout V Reg) - I dont detain one, Im still learning them, watching some yt videos, and it seems they actually [regulate] the voltage, meaning they are keeping it stable indiferent of the V source variation. Which is how i really like it. The downside on them that I observed is they are limited to 2V output and NOT lower. 2V is good enough in a way. But IF I NEED 1.5V sometime?
Edited here : a large majority i look over are 2V, also is mentioned pretty clear in some videos i watched, and it stuck in my head, but there are exceptions down to 1.2V. My indignation is because i wanted them to be perfect and go down to 0. But im getting used to them and learning them.
It really unsatisfied me this little detail. Eh well.

I need 3 separate Voltage sources from a 5V main V source.
The aspect i want illumination is: - Do i really need LDO? My voltage source does not fluctuate. Its fixed.
I need A=4V, B=3.3V and C=5V. And the source Voltage is 5V@1A.
Why is bad to use a Voltage Divider or ZD shunt regulator? For this case.
And why is so good to use LDO? I am really new to this component. Which i find it very attractive but im practical too (and cheap).

 

Depending on what you are trying to accomplish, those are TO-220 devices. There are also some lower overhead choices in TO-92.
Such as:
78L05 VOLTAGE REGULATOR 5V 100mA 5% PRECISION
78L09 VOLTAGE REGULATOR 9V 100mA 5% PRECISION
78L15 VOLTAGE REGULATOR 15V 100mA 5% PRECISION
TL431A ADJ PRECISION REGULATOR 2.5 - 30V 0.25A

Among others in all the various forms. It all depends on what you need to accomplish the task at hand that is within your power budget. The ones I listed are some of the common easily and cheaply obtained ones.

 

i also observed this package difference.
from TO-220 to TO-92 to D2Pak
For some weird reason, D2Pak versions are more expensive than the rest. Or I just look only for the TO-220 smd equivalents. For sure i didnt check every equivalent possible. You are free to correct me anytime. I will be glad if you find a powerful D2PAK way more cheaper than TO-220 or TO-92. Im refering to ebay market, and also I look on prices AND quantity - like 5pcs basically are the cheapest. But i found 10pcs also close to cheapness. (pcs means pieces).

 

SMDs are typically cheaper but hard to fit on a breadboard or protoboard. They do make adapters for SMD to through-hole pins but by then, the classic through-hole device is cheaper. Once again, it all depends on what you are wanting to do. For experimenting and breadboarding, through-hole for me. For production, SMD is the way to go but you will have to design and build the boards to use them. I do have some SMD devices that I use adapters for since they do not have the device available in a through-hole version. Power requirements have been shrinking for many years with devices to support that getting smaller.

 

Do they make modern LDO versions of the 78xx/79xx series ? And LM317/337 ?

So far I only ever salvaged LDO's.

 

All semiconductor manufacturers make Low Dropout (LDO) regulators. It is easy to search for them and see their datasheets. If you buy cheeep parts from ebay then who knows what they send to you.

 

For battery operation 5V LDO, 0.2V in a TO-220 package
consumers make it difficult.
For linear PS adding low noise in some applications.
The TO-220 package good for heat sinking, it does ok at keeping temperature constant.
in less constant low current application the TO-92 will work.
The dpak can be easy in some applications. Ebay did not have a really good regulator.
The really good regulators are not cost effective enough for consumers and need to be special ordered.

 

If you don’t need a lot of current the TLV431 voltage reference goes down to 1.24V. If for some reason you need even lower voltage at higher current you can divide a stable voltage to what you want, then buffer it with an opamp & transistor voltage follower.