YX 8018 joule thief Chip. I was trying to amplify the LED output via a transistor, more info in text

Please read the description first. A video about a “failed” experiment, trying to “amplify” the energy out of the joule chief chip, type number YX 8018. With a NPN transistor, the BD 139 (Silicium, Hfe between 70 and 150 in this case it was 150). Schematics are showed. Much more info/insights when reading this tekst.

Earlier video of 21 dec 2024 is here    • Small talk about the YX 8018, a joule...  

Connecting more than 1 LED (paralleled) to that YX 8018 did not work properly. The light energy divided over the 2 or more LEDS. Making them glow faint.

On the other hand: you can use that YX8018 to drive the BD 139 (with 10 Red LEDS paralleled in its collector lead, visible in the schematic). That bunch can take max. 1 Ampère….

But that “transistor” option does not work better compared to a situation where you put 3 (three) 1.5 batteries (Carbon Zinc or Alkaline) in series, giving out 3 x 1.5 Volt = 4.5 Volt and connect that “row” of 10 paralleled RED LEDS to that 4.5 Voltage supply. Via a resistor…..

A few things to tell (& disclaimer):

1. When 10 of these paralleled RED LEDS are connected to 3 fresh alkaline batteries of 1.5 Volt in series, the current that they take is extreme (!) (I measured 970 mA). Full Red light, of course…. In that case the 3 Carbon Zinc or Alkaline batteries will be depleted very soon, within minutes or an hour. Thus use a series resistor (0.5 Watt type) that limits the current.

2. Indicative values of that series resistor in case of 3 of these batteries are: 200 Ohm = 13 mA and 120 Ohm = 21 mA and 33 Ohm = 65 mA.

3. With a 220 Ohm resistor the voltage drop parallel to that resistor in this case is 2,7 Volt x (say) 15 mA. Means a loss of 2,7 x 15 = 40 Milliwatt inside the resistor. That is better (in terms of energy loss) compared to a situation where you use a Silicon transistor in the setup showed in this video. By the way: this refers to that 4,5 Volt supply voltage.

4. On higher supply voltages (say 12 Volt or so) it could be better to use a transistor, or, even better: a joule-thief-like transistor circuit (oscillator type) to loose as less energy in the voltage/current regulator as is possible, given the normal electronics laws. It will take time to develop it, anyway. Many of these step up-step down (voltage-current) chips are ready available from Ali.

5. A good option in this case (making a powerful LED light up on higher voltages, say 12 Volt or so, given this 10 paralleled red LEDS that can take almost 1 Ampère with the smalles energy loss possible) is the use of a CONSTANT CURRENT SOURCE. My earlier video (17 dec. 2024) about that is here    • Constant Current Source with 7805 dri...  

6. Test, try, experiment.

7. For safety (disclaimer) when you connect a power LED (or a bunch of paralleled LEDS, like used here) directly to a Voltage/Current source: always take measures to limit the maximum current. In the form of a resistor or whatever. To save problems in cases of a shortcut (safety resistor burns out and prevents scorche or heat, it prevents fire risk) or for another reason when the LEDS fail.

My You Tube channel trailer is here:    • Radiofun232 on YouTube. Updated month...  

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