Tesla Coil Not Working. Transistor Getting Extremely Hot

bertus

Joined Apr 5, 2008
21,683
Hello,

I see that schematic came from youtube.
Not all on youtube is correct.
You could try to flip the connections of the 3 turns coil.
Also the transistor is very small, it may need a heatsink.

Bertus
 

MrSalts

Joined Apr 2, 2020
738
What is the DC resistance of the 3-turns of copper wire? Once the circuit reaches steady state after you flip the switch, DC current will flow and, that current will be quite high. I imagine the resistance will be well under 1 ohm and, with 9v supply, you are drawing over 9amps (which is not possible with a 9v battery so I assume something between 1 and 2 amps until the bottom of the battery blows off from overheating).
The circuit is an "example" and a fast switching circuit should replace the physical switch. You can also add a capacitor in parallel with the battery to help average current flow out of the battery. Don't abuse that poor little 9v or, if you want to keep abusing it, wear safety glasses because they eventually pop.

The multivibrator circuit at 0:32 time stamp in the video of post #2 above is the right circuit to quickly turn on/off your Tesla coil. Watch the whole video. Don't skip steps.
 

Thread Starter

RohanRaj4245

Joined Sep 26, 2021
16
Hello,

I see that schematic came from youtube.
Not all on youtube is correct.
You could try to flip the connections of the 3 turns coil.
Also the transistor is very small, it may need a heatsink.

Bertus
I Bought a Tesla Coil on amazon. It is Working. Everything is connected and arranged according to youtube only. But mine is not working!!
 

Thread Starter

RohanRaj4245

Joined Sep 26, 2021
16
What is the DC resistance of the 3-turns of copper wire? Once the circuit reaches steady state after you flip the switch, DC current will flow and, that current will be quite high. I imagine the resistance will be well under 1 ohm and, with 9v supply, you are drawing over 9amps (which is not possible with a 9v battery so I assume something between 1 and 2 amps until the bottom of the battery blows off from overheating).
The circuit is an "example" and a fast switching circuit should replace the physical switch. You can also add a capacitor in parallel with the battery to help average current flow out of the battery. Don't abuse that poor little 9v or, if you want to keep abusing it, wear safety glasses because they eventually pop.

The multivibrator circuit at 0:32 time stamp in the video of post #2 above is the right circuit to quickly turn on/off your Tesla coil. Watch the whole video. Don't skip steps.
Can You Give me a circuit Diagram of which capacitor to add where and and my doubt is:- How many volts should i use? and Send the video link !!
 

ericgibbs

Joined Jan 29, 2010
14,234
hi Rohan,
How many terminals does your switch have.?

The builder used a 3 pole change over switch with the wires to the centre and one end connections.

The image shows a switch with wires to either end of the switch, if its a 3 pole switch it will not work.
E
EG 841.pngEG 842.png
 

ericgibbs

Joined Jan 29, 2010
14,234
hi,
That is not a photo shot, it is a circuit diagram.
Lets see how you have assembled it, photo.;)
E

What is the purpose of the LED.??? its not on the video.??
 

Audioguru again

Joined Oct 21, 2019
3,868
The LED probably conducts when the coil produces a negative voltage to the base of the transistor to turn it off. Then the maximum reverse emitter-base voltage (6V) is not exceeded.

It looks like only the very cheap battery and its wires limit the transistor current. Measure the battery voltage at the circuit when the transistor is warming up.
 

Audioguru again

Joined Oct 21, 2019
3,868
The photo has unmarked wires all over the place.

A 2N2222A is VERY old, some have their leads EBC and others are CBE. Which one is used here?
When the maximum-allowed emitter-base voltage of a transistor is exceeded then the transistor is ruined. The important missing LED protects this from happening.
 

Thread Starter

RohanRaj4245

Joined Sep 26, 2021
16
The LED probably conducts when the coil produces a negative voltage to the base of the transistor to turn it off. Then the maximum reverse emitter-base voltage (6V) is not exceeded.

It looks like only the very cheap battery and its wires limit the transistor current. Measure the battery voltage at the circuit when the transistor is warming up.
Should i use an led now? That is a new battery. ijust opened a battery from the package and connected it to my tesla coil
 

Thread Starter

RohanRaj4245

Joined Sep 26, 2021
16
The photo has unmarked wires all over the place.

A 2N2222A is VERY old, some have their leads EBC and others are CBE. Which one is used here?
When the maximum-allowed emitter-base voltage of a transistor is exceeded then the transistor is ruined. The important missing LED protects this from happening.
Can Capacitors Help ? i have capacitors . Should i connect them ?
 
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