9V 0.5A battery pack

Tom.G
There are two basic types of voltage regulators...
... The second type is 'linear regulator' , which keeps only current as constant
Hmm... I always thought voltage regulators regulated voltage. If they keep current constant, say at 100mA for instance, wouldn't a 10,000Ω load resistor have 1,000 Volts across it? Rather impressive for a 9V supply.

davenn

I've been trying to analyze this for a couple of days. This was what happened. Weeks ago. I glued the switch lever of the 5v-to-9v adaptor so the 9v can't be moved to 12v as I didn't want it to be exposed to 12v.

2 days ago. I tried to remove the glue because i want to set it to 12v to try a wifi router, but I ended up cutting a cooper in the PCB that connects the first terminal of the switch to another part of circuit.

Imagine a switch has 3 terminals. Terminal 1 & 2 makes it 9v. Terminal 2 and 3 makes it 12v. While the switch is in Terminal 1 & 2 making it 9v. I accidentally cut the cooper path to terminal 1. This means the switch momentary is neither 9v nor 12v. When I realized it and reconnected the cooper path. The device no longer works.

Do you have any idea what kind of design is the dc-dc converter (how many designs are there, I'm trying to google it but can't find the behavior) based on the youtube video above? When you turned it on (just turned on in the video), the LCD in the 5v-9v adaptor gets from 18v then down to 4.9v. The multimeter shows 15v to 5v when the output of the 5v-9v adaptor was connected. Note the dylos isn't connected to the above, of course because the output is connected to the multimeter. Thank you.

Here is the Dylos internal. I saw it shared by one user at amazon. The laser at the middle is aligned to the compartment below such that air is suck from the top to the bottom via the fan.

View attachment 257411
This is home wifi router. Many use the 5v to 9v adaptors to use the router it at car or coffee.

This was why I tried to use my 2nd working 5v to 9v adaptor and adjusted it to 12v when the cooper cut was made.

Here is what's so puzzling. The 5v to 12v adaptor is very useful in a lot of items. But how come they are all made in china. Doesn't the USA ever produce one? How come? I can't understand how the product is not useful in the United States.

Pending a USA made 5v to 12v adaptor. I connected the following battery pack with voltage and current meter.

I used the 6 pcs of partially discharged Energizer AA batteries and one ordinary battery. Just to test the usb volmeter & ammeter. I still need to buy 7 pcs of rechargeable NiMH and a fully automatic NiMH with negative delta capabilities. However. If I can buy a made in USA 5v to 9v adaptor. I may opt for the latter. So please advise on any product like it. Thank you.

This is not a battery charger. It is use to power various electronic pack such as kidtron (??) experimental board. As for battery meeting the requirement, they usually not rechargeable: Alkaline; Zinc-carbon, Lithium - 550mAh @ 9V.

`I bought the latest NiMH charger that can individually measure the charge and stop charging when it is full (with negative delta something capability).

With my 7 AA rechargeable NiMH batteries I connected my USB ammeter/voltmeter.

I realized the USB ammeter/voltmeter is only calibrated for 5v. This is because when the voltage is 8.9v. The current is wrong. Using a multimeter. The current is 270mA instead of 200mA.

Do you know another device like the USB ammeter/volmeter that can accurately display the current?

What kind of circuit is it that can only show accurate current if it is 5v only?

At least the voltage is more or less accurate and I can predict if the rechargeble AA NiMH batteries are about to get discharged.

I ordered another 5v-to-9v adaptor to power my router and the unit if i can't get a mini ammeter/voltmeter with display. It doesn't have to be USB.

(for some background of what is pm2.5 and stuff, see this i just read today https://edition.cnn.com/2020/02/25/health/most-polluted-cities-india-pakistan-intl-hnk/index.html )

I have this adaptor. Do you know what kind of battery power pack that can output at least 9 volts 0.5 ampere?

View attachment 256320

This is the spec sheet:

https://www.jameco.com/Jameco/Products/ProdDS/163628.pdf

It's the adaptor included in the world's cheapest (and only) 2 channel pm2.5 monitor. A 16 channel unit costs about $25000. This only costs$260 but it should be plugged into wall. If I can get a battery pack, I can bring it anywhere like outside. The manufacturer doesn't have any battery pack for it. They recommended using 20 meter extension to bring it outside, but it's too long, and didn't want to comment what kind of battery pack available for it because they have none.

https://www.amazon.com/gp/product/B004AWEG0Y/?tag=pfamazon01-20
The simplest solution would be to put 2 li-ion 1 A/h in series and try your device at that lower voltage (8 volts fully charged and 7.2 volts nominal). As far as I can tell, this will work with almost all devices that need 9 V.