Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

inverter for charging laptop

Status
Not open for further replies.
A

Arul271194

Newbie level 5
Joined
Dec 9, 2016
Messages
10
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
79
Inverter for charging electronic devices

I made an inverter circuit to charge laptop and mobiles and I got 150v Ac output but the problem with my circuit is when i connect my circuit with my laptop charger its charging and frequently disconnecting and charging .How to fix it here I have enclosed my circuit below

 

Re: Problem in inverter circuit

That is the horrible circuit at www.aaroncake.net that does not work because it is too simple.
You copied the schematic but made it a negative image, I made yours a positive image and show the original schematic with reasons why it does not work (one problem is that its backwards capacitors blow up!):

- - - Updated - - -

A fix to the circuit puts the capacitors with correct polarity and prevents the emitter-base junctions of the transistors from having avalanche breakdown (the breakdown damaged the transistors and caused very high currents in the capacitors) but:
1) The output will be a squarewave, not a sinewave like from mains electricity.
2) The peak voltage of the squarewave is much lower than the peak voltage from a normal sinewave.
3) The transistors get a low base current so the output power will be low.
 

Attachments

  • inverter.png
    inverter.png
    23.1 KB · Views: 105
  • bad inverter corrected.PNG
    bad inverter corrected.PNG
    6.3 KB · Views: 108
Re: Problem in inverter circuit

had same experience with that circuit , i tried to make it with 2N3055 . I got 220 v with very low efficiency
 

Re: Problem in inverter circuit

The problem with this 1950s-era multivibrator inverter is that it has absolutely no output voltage regulation.
The frequency will be all over the place.
Lastly to operate the transformer core is driven into saturation, which means terrible efficiency, high input current spikes, and transistor overheating.


Use a proper IC-driven design. The ubiquitous SG3525 was designed in the early 1980s, but it will allow you to build a far better inverter. There are tens of thousands of circuits on the web. Google it.
 

Re: Problem in inverter circuit

The transistors overheat when one is conducting and the other one is having avalanche breakdown. Most of the power from one transistor is heating the other transistor instead of driving the load.
The very high currents caused by the breakdown is also hard on the capacitors even if their polarity is corrected.
 

i have simulated many inverted circuits but i cant make my laptop charged with that circuit it is lagging i want clear idea about inverter circuit and which transformer i have to use
 
Last edited by a moderator:

Which specifications are you targeting? For a laptop I presume 19V DC output voltage, but which input voltage/frequency?
 

A laptop computer runs on DC, around 12V. Does your charger have a label stating 19V, 3A (as many do)? If so then you may find it is convenient to charge the laptop battery directly from a DC power source. It would require extreme care in design and construction, the same as when you build an inverter.
 

No guys i am asking for 12v dc to 110-220v ac output 50-60Hz ,my battery is 12v 6Ah i want to get Ac output to charge my laptop with laptop charger
 

Arul271194 said:
my battery is 12v 6Ah
Click to expand...

I believe your battery voltage will drop as soon as you try to draw enough Amperes to drive an inverter.

Even if it does not drop, you need to to minimize parasitic resistance in the 12V power loop. It is a challenge to succeed at this. You need to draw several Amperes from the battery constantly (probably between 5 and 10 A).

I purchased a small used inverter for 16 dollars on Ebay. It works from the cigarette lighter in the car. Something like this could be your quickest and most economical path.
 

Inverter for charging electronic devices

This inverter circuit is now driving enough power got confused
 

Attachments

  • Untitled.png
    Untitled.png
    14.2 KB · Views: 98
Last edited by a moderator:

Re: Inverter for charging electronic devices

Hi,

It's not clear what your question is.

Please give more detailed informations.

Klaus
 

Re: Inverter for charging electronic devices

I have implemented the above circuit its not giving enough power my laptop is not charging but my mobile gets charging.i dont no where the fault is.
 

Re: Inverter for charging electronic devices

Hi,

It seems you are asking us if this circuit is able to power your laptop.

Can you imagine HOW we can answer this?
..without knowing any specifications of the circuit...and without knowing the power requirements of your laptop.

In my eyes the only way is that you look for thise specifications, and as soon as you have them.. the question is answered.

Klaus
 

Some resistor values look dubious to me.

A straightforward method is to observe circuit waveforms without and with load and find out why the output is collapsing, Drop of battery voltage is one possible reason, also unsuitable transformer.
 

Why is your schematic a negative image? I fixed it again.

Your new circuit has power darlingtons all over it. Its oscillator transistors are missing the diodes I showed in my fix of the other inverter so they have avalanche breakdown instead of driving the rest of the circuit.
The output is a squarewave with its voltage reduced by the saturation voltage loss of the output darlingtons. Your multimeter and laptop cannot properly measure the squarewave voltage because they are expecting a sinewave from mains electricity that has a much higher peak voltage.
 

Attachments

  • inverter.png
    inverter.png
    23.9 KB · Views: 91

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top