Flyback Circuit How Do I Make A Saw Tooth Wave Generator For My Homemade Flyback?

How do i make a saw tooth wave generator for my homemade flyback? - flyback circuit

exactly what the title says .... How can I do? but I have run about 5 A at 12 V over him my flyback. this line here: http://www.powerlabs.org/images/schematic1.gif
that the circuit is good for a while, he no longer ran the amplifier is working as designed for 2N3055. (I ran instead of 5 amp rated 4), the clip was from my wave flyback and worked great, except that the transistor actually sorta run down and not work at all. Like a sawtooth wave generator that can produce will be delivered with at least 5 AMPS?