Joule Thief with Flip Flop

Joule Thief built with BC 549 transistor and toroid.

By means of an OA81 germanium diode and capacitor in parrallel with the 3 led's , I can charge a 4700 uF capacitor up to around 5 Volts dc, which is supplying a basic LED flip flop circuit built from discrete components.
2 x BC 549, 2 x 100 k, 2 x 680R, 2 x 22uF, 1 x blue, 1 x white LED.
The current drawn from the "flat" 1.5 Volt battery is about 23 mA's and the Voltage is 1.12 Volts.
The LED's are still flashing happily 4 hours after the video was taken.

17 May 2009 Flip Flop is still going fine. ( 4 days later )
Battery is down to 0.45 Volts, LED flash ratio is 3 Hertz

The stabilty of the circuit is excellent !

More experiments will follow soon.

http://i123.photobucket.com/albums/o298/RODALCO/Joulethiefwithflipflop.gif

Category:

Science & Technology

Tags:

• Joule
• thief
• flip
• flop
• BC549
• astable
• multivibrator
• LED
• germanium
• toroid
• 1.5
• Volts
• battery

[RODALCO2007]

@madamerotten Nope, that manderine just happened to be laying on the table

[DamoRC1]

Thanks so much for posting this working example. Two Questions. First, do I have to use a germanium diode GE1 - is there a specific reason not to use a regular diode. Second, can I leave out the three LEDs that form part of the Joule Thief portion of the circuit?

Thanks in Advance

[RODALCO2007]

@DamoRC1 You can use a normal diode.

The reason I use a germanium diode is less voltage drop 0.3 instead of 0.6 Volts.

The three led's in this case are acting as a zener diode and dropping about 5 Volts across the led's to allowe the flip flop to work reliably at about 5 Volts.

You could fit a 4V7 or 5V1 zener instead.

[man13preet]

This is very cool...because there is no use of IC and timers but only capacitor, diodes and resistors...ant schematics?

[RODALCO2007]

@man13preet Hi, there are a lot of great circuits to be built with simple discreet components.

[man13preet]

@RODALCO2007 can u give me the schematic??? it very very good.....cant we make a joule thief with iron rod instead of ferrite rod....what does ferrite rod do?

[RODALCO2007]

@man13preet It is at the text page by the video.

just click on the link.

You can try iron rod. not sure if that works well as the circuit oscillates at a high frequency. 8 - 16 kHz

[hardstyle905]

@Matthington10 dutch.

[Matthington10]

Love your accent :D

[madamerotten]

At 0:09, are you using the tangerine as a battery?

[ciprianwiner]

man thanks a lot ,i got lots of interesting effects just by changing some things around :D

[fitzgerald95971]

what is the practical application?

[projectNEMESIS001]

wow XD