SElabs tech blog

you said Joule Thief?  you said Joule Thief?  It’s a little wisp of a circuit that allows you to drive aPOWER  LED from a low voltage. Normally, if you want to light up a blue or white LED you need to provide it with 3 – 3.5 V, like from a 3 V lithium coin cell. But the magic of JT is  a 1.5 V battery like a AA cell simply will work.  Easy make  Joule Thief,  works like a charm. Not only does it work with a brand new battery, but it works until the battery is nearly dead– down to 0.3 V.  That’s well below the point where your other toys will tell you the battery is dead, so it can steal every last joule of energy from the battery (hence the name). how about a cellphone charger , yes it is doable , we are here to give you  a usable tested diagram . get  the ring toroid from a OLD smps of pc ! 

Vivo V7  Vivo Electronics Corp. is a phone brand based in Dongguan, Guangdong, China. It was founded in 2009. The company is another Chinese smartphone maker but this one spends more on dealer commission and IPL  To make the markets flooded with choices , they sale too many models .  Do you know vivo and OPPO are same cell companies .  Avid indian buyer  gets confused .  Vivo  tries to copy flagship product samsung/xiaomi  but it fails there are lots of segments  But to market the  vivo guys have many many  online comparision of OPPO Vs VIVO  1. Snapdragon 635 which heat phone very fast 2. Still screen resolution is low 3. Ram is low 4. No direct video call 5. Battery capacity low for that price  6. Camera focal lens is poor 7. Camera pics are over processed in software , look unnatural