ToddFun.com: Convert 120v AC to 12v DC using just a light bulb, diode and a capacitor.

How to hack a light bulb, diode and capacitor into a simple 12v DC power supply. I go into the math just enough so others can calculate the correct size light bulb for their 12v DC power supply hack.

Category:

Howto & Style

Tags:

• power
• supply
• hack

[fairyheli2]

what about 240v mains?

[toddrharrison]

@fairyheli2 Just the same, just do the math with 240v instead of 120v

[brade07]

@ZanzibarJose All LED's run on DC, the xmas lights would have some sort of rectifier/voltage regulator built into the plug usually. Id reccomend buying some for a car, led's are reltively cheap

[thepainballwolf]

you should be a teacher



[ZanzibarJose]

Let me ask you because some of it is still fuzzy to me. How could I run an LED light strip(Xmas lights) which use 120vac in my car using the 12vdc? What is it I need to do to rectify and step down the voltage so that I can patch this into the fuse panel and have it be operative?

[mikem1959]

Thank you for this video. This brings back memories. I was a electronics geek as a kid. I used to build kits and used the Radio Shack 150 in 1 to build many circuits.

[toddrharrison]

@nixxonnor NOTE: If you use a meter without LoZ voltage setting and you see voltage and think it is just ghost voltage you can get a 20watt to 40watt incandescent light bulb and connect it between the two points and if it glows a bit then you know it is not safe for the scope ground.

[toddrharrison]

@nixxonnor NOTE: check both AC and DC voltage. Try to use a meter with Auto-V LoZ voltage setting like the Fluke 117. This way it will auto show high voltage either AC or DC and with low impedance so you will not see ghost voltages and think it is unsafe to connect the scope ground.

[toddrharrison]

@nixxonnor I’m not sure what you’re getting at here. If you want to know if it is safe to connect your ground clip of your scope to a point on your DUT or power system just meter the voltage between the point and your ground clip. If it is not zero or very much close to zero then DON’T connect the ground clip.

[nixxonnor]

@toddrharrison Does that mean that both the outputs of the DC converter is electrically isolated from the mains? Is there a way to be absolutely certain (ie using a multimeter) that any AC-DC converter is acting as an galvanic isolator? (Do I have an isolation transformer for sure if resistance between in and out connectors are infinite)