Lasersaber strikes again. A joule thief king ?

[MarkE]

@MarkE: thank you for your input, the DMG1012 looks very interesting, just the right transistor to be driven by a TLV2401 multivibrator narrow square wave.

I will go in the direction of driving a 220V LED lamp with two AAA batteries and the multivibrator. The 2 V to 3 V from two 1.5 AAA or AA batteries seem to be just right.

What I have to do now is find or wind the right transformer, but I have a few sitting somewhere in my house. I think that a useful emergency light or flash light can be done with 0.1 Watt.

I found that a LED needs at least 1 mW to shine brightly, and there are plenty of Joule Thiefs doing that nicely.

Greetings, Conrad

If your goal isn't chasing the lowest power still visible LED but to have a useful long lasting light powered by one or a couple of AAA cells then there are some very good options out there.   I think that 10 lumens is kind of the low end of useful light.  With the right LED you can get that on 80mW to the LED and a little more than 100mW drawn from the batteries.  A pair of AAA batteries gets you more or less 2Wh.  So you could go for 200 hours on such a circuit.

[conradelektro]

I just saw a replication of LaserSaber's low power Joule Ringer on YouTube https://www.youtube.com/watch?v=h-_aWDt79fw (by itsusable)

Greetings, Conrad

 

[conradelektro]

Just wanted to try with a little fly back transformer. Could be optimised with a more suitable MOSFET (depends on power supply and LED lamp Wattage). The duty cycle has to be adjusted to the particular LED lamp.

I went for a two battery (2.5 V to 3 V) or three battery (3 V to 4.5 V) power supply and a low Wattage 220V LED lamp (0.7 Watt to 3 Watt).

At around 4 V and ~100 mA (about 0.4 Watt) one has a very useful low Wattage LED lamp (220V 0.7W to 3 Watt LED lamp). But also around 3 V and ~30 mA (about 0.1 Watt) the LED lamp starts to be useful.

May be the whole thing is not of much use. I wanted to show that an OpAmp astable multivibrator can be used to create a LED or LED lamp driver. I was surprised that it is today very easy to create an OpAmp based astable multivibrator which operates at a few µA. Of course, the real up to date design would be a microprocessor based circuit which would offer a very high flexibility. The modern 16 Bit microprocessors also operate at a few µA, there are even some which work down to 0.9 Volt (45 µA active mode).

http://www.ti.com/lsds/ti/microcontroller/16-bit_msp430/low_voltage/overview.page?paramCriteria=no

Once I get some 2N1304 germanium transistors, I will have one more go at a LaserSaber Super Joule Ringer replication.

Greetings, Conrad

[Pirate88179]

Has any one tried the Touchstone TS3002 chip with their demo board yet?  This has an amp draw of less than 1 micro amp.  I happen to have one of these demo boards and will dig it out and see what happens.  I also have about 6 spare chips for it.

This should be able to drive an led for a very, very long time.

Bill

[d3x0r]

Just wanted to try with a little fly back transformer. Could be optimised with a more suitable MOSFET (depends on power supply and LED lamp Wattage). The duty cycle has to be adjusted to the particular LED lamp.

I went for a two battery (2.5 V to 3 V) or three battery (3 V to 4.5 V) power supply and a low Wattage 220V LED lamp (0.7 Watt to 3 Watt).

At around 4 V and ~100 mA (about 0.4 Watt) one has a very useful low Wattage LED lamp (220V 0.7W to 3 Watt LED lamp). But also around 3 V and ~30 mA (about 0.1 Watt) the LED lamp starts to be useful.

May be the whole thing is not of much use. I wanted to show that an OpAmp astable multivibrator can be used to create a LED or LED lamp driver. I was surprised that it is today very easy to create an OpAmp based astable multivibrator which operates at a few µA. Of course, the real up to date design would be a microprocessor based circuit which would offer a very high flexibility. The modern 16 Bit microprocessors also operate at a few µA, there are even some which work down to 0.9 Volt (45 µA active mode).

http://www.ti.com/lsds/ti/microcontroller/16-bit_msp430/low_voltage/overview.page?paramCriteria=no

Once I get some 2N1304 germanium transistors, I will have one more go at a LaserSaber Super Joule Ringer replication.

Greetings, Conrad

the last model was built with mpsa16 which has low gate on voltage; NTE47 equivalent