Hey guys,

I have built a 555 timer circuit, which in turn drives a TIP41C to power a flyback. http://tacashi.tripod.com/elctrncs/555sstc/555sstc.gif is the circuit, exept i swapped out the said transistor for the TIP41C equiv. The problem is the output arc is VERY weak, less than 1cm. I have 12V @ 4A input, and that gave me VERY big arcs with a 2N3055 circuit, so i dont know why it isnt doing that here. is there any changes i need to make to this circuit to accept the other transistor? I feel that the transistor isn't letting enough power through, but i have no idea how to change this. Also, apparently you can chnage the 1K and 2.2K resistors, and 10nf cap to vary the freuency of the 555, what are safe rsistances to stick with, since i dont really wanna blow anything up

__________________
The 3 laws of science....
1. If it smells bad, It's chemistry.
2. If it's mushy, It's biology.
3. If it doesn't work, It's physics.
www.laserpointerforums.com A forum for disscusion of lasers and laser shows!
www.laserchat.org IRC chat for laser and electronic related stuff.

 

BTW i tried 2 different flybacks, so its not my flyback. Also this is for a singing arc, so the audio goes into pin 5 of the 555 with a .1uf cap across + and -.

__________________
The 3 laws of science....
1. If it smells bad, It's chemistry.
2. If it's mushy, It's biology.
3. If it doesn't work, It's physics.
www.laserpointerforums.com A forum for disscusion of lasers and laser shows!
www.laserchat.org IRC chat for laser and electronic related stuff.

 

Your link to the circuit shows nothing. Please copy the schematic and attach it here.

a 2N3055 has a max allowed collector current of 15a.
a TIP41 has a max allowed collector current of only 6A so maybe it breaks in the circuit.

__________________
Uncle $crooge

 

Oh woops....

Here is the circuit i made...

555sstctip.GIF

__________________
The 3 laws of science....
1. If it smells bad, It's chemistry.
2. If it's mushy, It's biology.
3. If it doesn't work, It's physics.
www.laserpointerforums.com A forum for disscusion of lasers and laser shows!
www.laserchat.org IRC chat for laser and electronic related stuff.

 

well the sound works fine, i just really need to get more power into this arc, it can barely keep itself together, and the transistor is getting very hot as it is....

__________________
The 3 laws of science....
1. If it smells bad, It's chemistry.
2. If it's mushy, It's biology.
3. If it doesn't work, It's physics.
www.laserpointerforums.com A forum for disscusion of lasers and laser shows!
www.laserchat.org IRC chat for laser and electronic related stuff.

 

No one has any idea?

__________________
The 3 laws of science....
1. If it smells bad, It's chemistry.
2. If it's mushy, It's biology.
3. If it doesn't work, It's physics.
www.laserpointerforums.com A forum for disscusion of lasers and laser shows!
www.laserchat.org IRC chat for laser and electronic related stuff.

 

The transistor will be hot if it conducts too much current for its rating.
It will also be hot and the output power will be low if the transistor does not have enough base current so it does not conduct fully.

The 50 ohm base resistor gives the transistor a base current of 180mA when the supoply is 12V. Then it conducts well when its collector current is no higher than only 1.8A.

The 555 will fry if the base resistor has its value reduced.
If the TIP41 transistor is replaced by a TIP147 darlington transistor then the circuit will work better.

__________________
Uncle $crooge

 

Be sure to isolate the transistor with a suitable heatsink, or you will fry more than the circuit. Are you building a stun gun, electric fence or CRT/flyback tester?