Lasersaber strikes again. A joule thief king ?

[alejandroguille]

LaserSaber published his latest circuit, see at http://laserhacker.com/?p=406

He seems to use the coil as described here http://laserhacker.com/?p=401

Attached please see a circuit diagram which compares my replication with his creation. My replication is much worse concerning run time with an electrolytic  capacitor. LaserSaber's creation runs for many minutes with a 3000 µF cap, mine only runs about 2 minutes with a 4700 µF cap.

You can see more details here http://www.overunity.com/14591/lasesaber-strikes-again-a-joule-thief-king/msg402222/#msg402222


I am waiting for the delivery of some 2N1304 germanium transistors (bought on eBay), but I will add a copper strip to the outside of the second winding (which is connected to the base of the transistor, after removing the unused third winding). We will see if it changes anything. The copper strip on the outside can easily be added and removed again.

I want to try the coil with a 2N1304 transistor before completely dismantling and rewinding it with two copper strips, one of which should be the first layer. We need the comparison of a coil with and without copper strips.

Before going into pot cores I want to do tests with this more conventional core.

Greetings, Conrad

thank you!

[Pirate88179]

  Many of the ferrite e-cores that are used in pc monitors and tv sets use a copper strip on the outside of the ferrite core, so there must be a good reason for this.
  Those that can't find copper foil, might try using a strip of aluminum cut out of a soda can.

Not a bad idea Nick, but I would caution folks to burn off the plastic liner used on the inside of the cans to allow electrical contact in case that is important.  A simple continuity test could show if the liner has been removed enough.

Bill

[d3x0r]

2n1304; these are kind of hard to find; only a few germanium transistors are being produced apparently.


saw this demo; they do guitar effects pedals and explain the difference between germanium and silicon diodes for this application..
https://robertkeeley.com/2013/09/germanium-transistors/


lost_bro commented that it has a 0.22V Vbe on.  That's incredibly low; and I can't find any silicon near that.


Did buy some 34/22 3000 perm pot core and some mc34063;


If someone stumbles on a replacement part for the 2n1304 I'd be interested

[conradelektro]

I added a copper strip to the outside of the coil (see attached photo). The third winding has been removed.

The circuit is still the same, see:
http://www.overunity.com/14591/lasesaber-strikes-again-a-joule-thief-king/msg402255/#msg402255
http://www.overunity.com/14591/lasesaber-strikes-again-a-joule-thief-king/msg402222/#msg402222

With the copper strip (and an unchanged circuit) the power consumption has gone up considerably fom less than 1 mA to 6 mA at 1.5 Volt (more at higher Voltages). The LED shines brighter. The circuit also has problems starting up, most of the time one has to touch the copper strip to start oscillation.

Connecting the copper strip to any winding (at any side) has no discernible influence on the behaviour of the circuit.

The copper strip has changed the properties of the coil towards more power consumption and start up difficulties (with the same circuit as before addition of the copper strip). The circuit has to be changed to accommodate the chages in the coil.

Greetings, Conrad

[Dave45]

https://www.youtube.com/watch?v=rpGOKGrcpAk