I’ve used a 2-NPN transistor array (BC846S) with a 470uH ferrite choke for several years with great success. The only difference from my circuit and this is I don’t use a 10uF capacitor across the battery. Is this necessary? Should I experiment with my JT circuit. I’m always looking for the least mA draw from the battery and of course the biggest light. Thanks for this post! I love these circuits.
Kris R. Columbus, OH
The 10 uF is optional, but highly recommended. It helps when the battery internal resistance gets higher, as the cell is being depleted and nearly dead. Try it with and without and see what you think. If you think the cost is too high, just get some old keyboard or mouse or other electronic device and unsolder a capacitor from the PC board. It really doesn’t matter what the value is. You can use anywhere from those “104” ceramic disk caps to a thousand microfarad, if you don’t mind the large size. If you want to get the same light but use half the current, you can try my Supercharged Joule Thief.
I’ve used a 2-NPN transistor array (BC846S) with a 470uH ferrite choke for several years with great success. The only difference from my circuit and this is I don’t use a 10uF capacitor across the battery. Is this necessary? Should I experiment with my JT circuit. I’m always looking for the least mA draw from the battery and of course the biggest light. Thanks for this post! I love these circuits.
Kris R. Columbus, OH
The 10 uF is optional, but highly recommended. It helps when the battery internal resistance gets higher, as the cell is being depleted and nearly dead. Try it with and without and see what you think. If you think the cost is too high, just get some old keyboard or mouse or other electronic device and unsolder a capacitor from the PC board. It really doesn’t matter what the value is. You can use anywhere from those “104” ceramic disk caps to a thousand microfarad, if you don’t mind the large size. If you want to get the same light but use half the current, you can try my Supercharged Joule Thief.