Learning Circuit Inspires "The Watch Stand"

RE: Learning Circuit Inspires "The Watch Stand"

jw0752 — Mon, 11 Feb 2019 03:29:43 GMT

Addendum:

I have continued to experiment with the Battery Juicer / Joule Thief circuit to learn more about how it is affected by different transistors and different transformers. Obviously the choice of transformer and transistor have a significant effect on the output and frequency of the circuit. There was one result that while not unexpected seemed worthwhile reporting. If one really wants to suck the batteries to the lowest level it is important to use a Germanium Transistor.

I set up an experiment with a 151-0121 Silicon NPN transistor and the lowest voltage that would start and maintain oscillation in the Joule Thief was 0.603 Volts. The same circuit using a 2N1304 NPN Germanium went down to 0.2 Volts. I doubt that the energy content of the battery is a linear function of the voltage but just the same here we have additional usable content in the battery as it drops from 0.6 volts to 0.2 volts that can be harvested by a Ge transistor and which is out of reach to the Si Transistor.

John

RE: Learning Circuit Inspires "The Watch Stand"

shabaz — Thu, 07 Feb 2019 12:17:20 GMT

Hi John,

Nice project! How are you holding the shapes together while soldering? You're getting great use out of the round-nose pliers : )

RE: Learning Circuit Inspires "The Watch Stand"

dougw — Wed, 06 Feb 2019 22:07:27 GMT

Another great 12 gauge project.

That could be a Project 14 theme...

Your project also brings up the question of what to do with all our old watches.

I no longer wear a watch, but I still have a small collection that has sentimental value.

RE: Learning Circuit Inspires "The Watch Stand"

DAB — Wed, 06 Feb 2019 20:32:45 GMT

Great project John.

Perfect application to suck the last life out of old batteries.

DAB

RE: Learning Circuit Inspires "The Watch Stand"

fmilburn — Wed, 06 Feb 2019 17:59:59 GMT

Hi John,

So refined and artsy... If only it used a Raspberry Pi it would be a sure winner in the PIcasso contest :-)

Frank

RE: Learning Circuit Inspires "The Watch Stand"

mayermakes — Wed, 06 Feb 2019 17:25:14 GMT

Absolutely amazing! I really like your idea, and great use case for the joule thief!

RE: Learning Circuit Inspires "The Watch Stand"

rachaelp — Wed, 06 Feb 2019 16:10:02 GMT

Excellent work John, it looks really cool and very useful to have to see your watch in the night. Definitely a very nice project!

Best Regards,

Rachael