What you can get for a Buck.

Thread Starter

RichardO

Joined May 4, 2013
2,270
I had some time to kill and I ended up in a Dollar Tree. (For those not in the US, everything costs exactly a US dollar).

I splurged on a 12V to 5 volt adapter for charging cell phones in a car.

The charger is a switch mode power supply. As you can see from the picture there are not many parts.
The PCB only has 6 electonic parts on it -- 2 electrolytic caps, an inductor, a rectifier diode, an LED and the switcher chip. Also of value is an itty bitty fuse, screw and a spring.

The chip has a logo I don't recognize. It has 3 concentric partial circles with inner circle having an inward pointing arrow. It's marked with 5073 and AD84064Q.

I have included the data sheet. You do read Japanese (Korean?) don't you?
Note the size of the AD84064Q. It is an 8-pin DIP with 1.8mm (about 0.070") lead space.

OneBuckSwitcher.JPG
 

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hp1729

Joined Nov 23, 2015
2,304
I had some time to kill and I ended up in a Dollar Tree. (For those not in the US, everything costs exactly a US dollar).

I splurged on a 12V to 5 volt adapter for charging cell phones in a car.

The charger is a switch mode power supply. As you can see from the picture there are not many parts.
The PCB only has 6 electonic parts on it -- 2 electrolytic caps, an inductor, a rectifier diode, an LED and the switcher chip. Also of value is an itty bitty fuse, screw and a spring.

The chip has a logo I don't recognize. It has 3 concentric partial circles with inner circle having an inward pointing arrow. It's marked with 5073 and AD84064Q.

I have included the data sheet. You do read Japanese (Korean?) don't you?
Note the size of the AD84064Q. It is an 8-pin DIP with 1.8mm (about 0.070") lead space.

View attachment 121950
Good find!
 

#12

Joined Nov 30, 2010
18,224
You must be some kind of engineer type of person. Everything comes apart, even if it's new!:D
Same here. The first thing that happened to my new welder was that it came apart so I could figure out how it works...and replace some of the absurd wiring. A 50 amp plug on a 14 gauge wire???:eek:
Guess again.:D
 

Thread Starter

RichardO

Joined May 4, 2013
2,270
You must be some kind of engineer type of person. Everything comes apart, even if it's new!:D
I once bought a metal detector for my dad. I made the mistake of telling the sales person that I was going to open it up to see how it worked. I got a horrified "You can't do that". It turned out that case had to be opened just to install a battery. So much for knowledgeable sales people.

I have learned a lot by opening things up. One of my favorites was a specialized IR remote control. It used carbon ink as the second layer on a single sided PCB to wire up the push button switches! Now, that is really cheap (in all meanings of the word). I don't think I have the remote anymore. I bought 2 -- one to use and one to take apart. When I told friends what it did they wanted one. So I gave them both away. I had already gotten my monies worth so I don't think I bought another one.
 

Kjeldgaard

Joined Apr 7, 2016
476
It looks like a (AP/KA/MC) 34063 with some extra resistors.

Same relatively low switching frequency, external flyback diode, Darlington switch transistor and 100 uH inductor.
 

#12

Joined Nov 30, 2010
18,224
"You can't do that".
I do that so often that my family has named the process after me.:cool:
A lot of my instructions start with, "First, you void the warranty".
For instance, add-on car mirrors. If you just install them, the mirror surface will be ruined by moisture in 90 days. First, you void the warranty by peeling the back off. Then you give the back side of the mirror 3 coats of Krylon Clear. Put it back together and it will last for years.;)
 

Thread Starter

RichardO

Joined May 4, 2013
2,270
It looks like a (AP/KA/MC) 34063 with some extra resistors.
Same relatively low switching frequency, external flyback diode, Darlington switch transistor and 100 uH inductor.
Oddly enough, that is one reason I bought the adapter. Not long ago I remarked to a friend that I had just learned that the MC34063 was a version of the classic uA78S40. He said he did not know the connection either but that the MC34063 was used in a lot of adapters.
 

spinnaker

Joined Oct 29, 2009
7,830
Oddly enough, that is one reason I bought the adapter. Not long ago I remarked to a friend that I had just learned that the MC34063 was a version of the classic uA78S40. He said he did not know the connection either but that the MC34063 was used in a lot of adapters.
The 34063 has been around a long time. There are probably a lot more efficient chips out there now but few so versatile and well supported.
 

ErnieM

Joined Apr 24, 2011
8,377
I've bought things just to see how they do it for so little money. The one that comes to mind was an Ikea nightlight, half ball you plue into an outlet and it shines a LED downwards when the room is dark.

I just had to open that sucker up to see the magic inside. No transformer or inductors
BTW.
 

Thread Starter

RichardO

Joined May 4, 2013
2,270
Here are pictures of a solar sunflower.
Solar_sunflower.JPG Solar_sunflower_circuit_close.JPG Solar_sunflower_back.JPG
So, what do you get for a buck? You get a solar cell, a coil and maybe a magnet and not much else. The chip is under the epoxy blob and is not useful for much.

What you mostly get is some insight on how clever the mechanical design is. It is mechanically resonant with very low friction bearings. This is why it works with just the light from a flashlight. You will have to invest your own dollar to see in detail how it works.
 

radiohead

Joined May 28, 2009
514
I've bought things just to see how they do it for so little money. The one that comes to mind was an Ikea nightlight, half ball you plue into an outlet and it shines a LED downwards when the room is dark.

I just had to open that sucker up to see the magic inside. No transformer or inductors
BTW.
You sure its an LED and not an neon lamp? The neon lamp is still a good find for a dollar.
 

radiohead

Joined May 28, 2009
514
I like the dollar tree laser pointer/LED keychain.
For $1 you get:

a laser driver (with adjustable end to focus laser)
a bright LED
two tactile switches
three small button batteries
 

Thread Starter

RichardO

Joined May 4, 2013
2,270
I got tired of setting up the tripod to take close up pictures of small items so I built this stand using a pair of Dollar Tree rulers. They were 2 for a dollar. :D The reason for using rulers was so I could include a scale reference in the photos.

Even though the rulers are made of wood they are surprisingly stiff. In fact the weak point is at the bend at the base of the vertical, metal, back plate.

Closeup_stand.JPG
 

Thread Starter

RichardO

Joined May 4, 2013
2,270
Harbor Freight has diamond cutoff wheels for Dremel tools at 5 for $7. That is just over a buck each with one of their 20% discount coupons.
These discs are great for cutting plastic. Surprisingly, they do not clog up.

They work well for opening battery packs and wall warts that are heat or sonically welded shut.

upload_2017-12-31_9-35-10.jpeg
 

Thread Starter

RichardO

Joined May 4, 2013
2,270
I found a 120vac USB battery charger at Dollar Tree. It has the ac plug on one end and a USB connector on the other.

USB_ac_bot.JPG USB_ac_top.JPG USB_ac_side.JPG USB_ac_side2.JPG USB_ac_end.JPG

Observations:
The ac plug does not solder to the PCB. The ends of the plug make contact by poking into springs on the end of the PCB.
What appears to be a CR5212 is probably the switcher controller. I have not found data on the part.
When I get bored I will draw the schematic.
 
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