Wireless powered led project failture. Help needed

Hi bros.
I managed to power on a led lamp with wireless power transfer, i just found 2 circuits one with 2n2222 & another with bd135(if i remember)
Any ways i followed this design:


But with 2n2222a (metal cap)transistor and after stugelling aloooot i could turn on the led but i realized that its veryyyyyyy dim & the trans. Is getting too hot for the touch and after this over heat circuit didnt work again
circuit using 2n2222a instead of normal one(2n2222):

Online guide:
https://youtu.be/-7DgPmkg-74
--note that i just made one turn with thick wire for led instead of 30 turns,so i think the reason for dim led but the whole circuit is unstable and thats the real problem

You are trying to use a Harley oscillator as a transmitter? You need to design the transmitter from the grounds up and measure the values and select the operating point of the transistor carefully.

c_mitra said:

You are trying to use a Harley oscillator as a transmitter? You need to design the transmitter from the grounds up and measure the values and select the operating point of the transistor carefully.

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So how����whats the problem of this design,sorry but im noob !
My power source is a mobile charger and im not gonna change it for some reasons(makes buzz when connected to circuit)

Mobile chargers can provide max 0.5A at 5V and that may be sufficient for your purpose.

But how about the circuit? Is that a Harley oscillator? What is the design frequency? What are the inductor values? Where is the capacitor?

c_mitra said:

Mobile chargers can provide max 0.5A at 5V and that may be sufficient for your purpose.

But how about the circuit? Is that a Harley oscillator? What is the design frequency? What are the inductor values? Where is the capacitor?

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I dont know any thing about harley design or frequency��
As i described i just copied circuit from online source,no capacitor.why i need one?!!
Inductor has 30 turns totaly at the 15th turn i made a knot and conected it to + terminal...

I strongly suggest that you read about the Hartley oscillator and look up specific designs for simple circuits. You look for a design frequency of 30-50 kHz (it will change once the power transfer takes place) and use a good DMM to measure the inductance values. Once the circuit is operational, you need to record various parameters and measure the energy transfer efficiencies.

The circuit is one way to make a blocking oscillator. A capacitor is not needed. The 1k base resistor reduces the base current to a low amount so it can work from a 1.5V battery. If a 5V power supply is used then the resistor value must be increased 5V/1.5V= 3.33 times to prevent burning out the transistor.

Learn about the turns ratio of a transformer to see that a transmitter coil with 30 turns but a receiver coil with only one turn will not work.

Audioguru said:

The circuit is one way to make a blocking oscillator. A capacitor is not needed. The 1k base resistor reduces the base current to a low amount so it can work from a 1.5V battery. If a 5V power supply is used then the resistor value must be increased 5V/1.5V= 3.33 times to prevent burning out the transistor.

Click to expand...

But an aa battery is almost 0.5 amps too :|
Whats highest current rate of that transistor?

Learn about the turns ratio of a transformer to see that a transmitter coil with 30 turns but a receiver coil with only one turn will not work.

Click to expand...

I know i must have a reciver with more than 30 turns but i ran out of isulated wire

An AA battery cell can deliver 9 Amperes if it is a good one, not a cheap Chinese "super heavy duty" piece of junk. The circuit is supposed to limit the current, not the battery.

The datasheet for a 2N2222A transistor shows its maximum allowed current is 800mA (0.8A). Its current gain at a current of 150mA is from 100 to 300.
Then with a 1.5V battery, a base resistor of 1k its base current is (1.5V - 0.7V)/1k= 0.8mA and its collector current will be 0.8mA x 100= 80mA to 0.8mA x 300= 240mA which is well within its allowed current.

With your 5V power supply then the base current is (5V - 0.7V)/1k= 4.3mA and if the transistor has a current gain of 300 then the collector current might be 4.3mA x 300= 1290mA and the transistor might blow up. But the current gain is less at high currents (minimum of 30 at a current of 500mA) so maybe the transistor will survive if it goes not get too hot.

Audioguru said:

An AA battery cell can deliver 9 Amperes if it is a good one, not a cheap Chinese "super heavy duty" piece of junk. The circuit is supposed to limit the current, not the battery.

The datasheet for a 2N2222A transistor shows its maximum allowed current is 800mA (0.8A). Its current gain at a current of 150mA is from 100 to 300.
Then with a 1.5V battery, a base resistor of 1k its base current is (1.5V - 0.7V)/1k= 0.8mA and its collector current will be 0.8mA x 100= 80mA to 0.8mA x 300= 240mA which is well within its allowed current.

With your 5V power supply then the base current is (5V - 0.7V)/1k= 4.3mA and if the transistor has a current gain of 300 then the collector current might be 4.3mA x 300= 1290mA and the transistor might blow up. But the current gain is less at high currents (minimum of 30 at a current of 500mA) so maybe the transistor will survive if it goes not get too hot.

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Thanks maaaan ill try it with my last transistor ,pray for me :crying:
Will do it with 3kresistor as you said but but but bro if i fail again should i go for
Thiss design :

i think this can handle more power and works with more distance

You know what? Your 2N2222A transistor in a metal can is so old that if you bought it recently then it might be a fake and will not work properly.
If the transistor meets the spec's in its datasheet then with a 5V supply the base resistor must be 3.3k or more, not 3k. I did not calculate the heating in the transistor, it might fail from getting too hot.

The huge, high current and high voltage old TIP35C transistor is a joke to be used in this very simple circuit, isn't it?

Hi,

Maybe a "medium power" transistor is a suitable substitute for the 2222. The 2N4921 was the first example in the search result, no other reason for posting the link:

https://www.onsemi.com/PowerSolutions/product.do?id=2N4921

I agree with the last post, I wouldn't use a high power BJT like the TIP35C... Sledgehammers and hammers do different jobs

Does this project have a useful function? A high current in the transmitter coil produces a low current in the receiver coil and the coils must be touching. It might be able to charge a phone but it will take a very long time.

d123 said:

Hi,

Maybe a "medium power" transistor is a suitable substitute for the 2222. The 2N4921 was the first example in the search result, no other reason for posting the link:

https://www.onsemi.com/PowerSolutions/product.do?id=2N4921

I agree with the last post, I wouldn't use a high power BJT like the TIP35C... Sledgehammers and hammers do different jobs

Click to expand...

Ok so you say i should use 4921 instead of that , whats the advantage ?
And ill be happy if you post me circuit

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Audioguru said:

Does this project have a useful function? A high current in the transmitter coil produces a low current in the receiver coil and the coils must be touching. It might be able to charge a phone but it will take a very long time.

Click to expand...

Yes they are exactly almost touching , but withtip35 it seens to be better

Hi,

The 4921 is only as an example of a medium power transistor, there will be thousands of others that may be more apt for your circuit. At a guess, I'd suggest using a BJT rated for 3 Amps continuous current, with as low a VBE as you can find (that isn't stupidly expensive), and read the datasheet specifications, at least look for the graph called "Safe Operating Area" to check it can actually handle 0.5A at 5V continuously, even if it's described as "3 Amps continuous current" in the description.

There's usually a "Digikey" link here on EDA, it'll have a super parametric search tool to locate the right transistor quickly, it's always good to compare a few datasheets, even if it takes a little time, to select what's right for the circuit you are building.

I'm sorry, I am unfamiliar with your circuit in several ways, so it would be inadvisable to attempt to provide a schematic for you. Whatever you do, if the webpage you are following for the design is reputable/sensible/seems to have tested the circuit themself/etc, if you don't follow the instructions properly it's unlikely to work.

The 2N2222A, whether plastic or the metal capped version, which I like capriciously, is a little transistor that isn't really suited to operating at half an Amp at all, the TIP35 is a high power device meant for much larger currents which you don't need, so: "not too hot, not too cold, but just right" would presumably mean a medium power transistor, that's the difference in my opinion.

If it works with the TIP35, then fine, seems OTT. Hope you have a DMM, as important as the circuit. If you ran out of insulated wire, don't you have any old broken electronic or household device you might be able to salvage some similar wire from?