High Efficiency Lamp Driver

[joellagace]

Not very scientific at this point but I must point out the reactance thing does work with tiny generators, I tried it with a toy sized hobby PMM generator motor. The frequency you need to watch for as that is how X capacitor is calculated. So if your generator operates at an odd frequency your going to have to calculate some new capacitor value. Or it wont operate as intended.

How ever I have offered some alternatives to get more or less the same results and same current inputs with just a few extra parts and a spark gap stage for those who fear the reactance instead of using the x cap setup.

[Dog-One]

The current limiter as per ohms law x= 1/2*3.14fc
I = v/x

So 60 hertz with around 1uf gives us about 40 ma of current only!

Help me out with my math please:

V = 110 (Volts)
F = 60 (Hertz)
I = 0.04 (Amps)
C = 0.000001 (Farads)

X = V / I = 110 / 0.04 = 2750 (Ohms) = (PI  * F * C) / 2 = (PI * 60 * 0.000001) / 2

That doesn't compute.  What have got wrong here?

I was shooting for an equation solving for C, so I'd have that handy as a starting place for which capacitor to use.

[joellagace]

to be honest I just use the math from this site as a basic reference and what I don't get I just punch in online calculators to help me out.

https://circuitdigest.com/electronic-circuits/transformerless-power-supply

So if its not 40ma then what is it? from the chart on that site and all the calculations I run in the calculator for X I find online.  It is indeed going to be a small value what ever it may be. But if there is an error in calculation would be nice to know the specifics.
Thanks

[joellagace]

High Efficiency Lamp Driver Back EMF Version.

https://www.youtube.com/watch?v=3ju0WJfpwso

After some criticism over some of my reactive circuits,  I quickly put together this working demonstration that we can do the same thing via other methods, its all about limiting the current to its lowest value we need so we don't have to pay much. the previous x reactance method was just one of the many.

Here I use a low voltage square wave generator that operates at around 5 volts. This triggers a base resistor of NPN transistor to switch my 9 volts battery into a home built 1.9 ohm air core coil, quicky wounded with telephone cable. About 300 feet of it.

We feed the high voltage backEMF with the help of diodes Bedini style and quickly charge a 10uf cap to 100 volts with very little current thanks to the sharp low 10% duty cycle holding back much of the current from leaving that 9 volt battery but in return produce loads of back emf for quick charging and discharging of 10uf capacitor at 100 volts thanks to the SCR neon capacitor dump. We store this charge into a set of 12 volt supercapacitors this gives us steady dc in return enough to run that little high frequency inverter and drive the lamp just fine at its full lumens normally needing 15 watts at 60 hertz AC! It's clear here this little 9 volts can't produce "15" watts on it's own without the help of some additional systems, pulsing, electrets, super caps, high frequency etc... thanks to running the circuit mostly as an open loop.

It's a more complicated circuit but it further proves the concept. What you can do with very little current if you know how to utilize it.

[Dog-One]

to be honest I just use the math from this site as a basic reference and what I don't get I just punch in online calculators to help me out.

https://circuitdigest.com/electronic-circuits/transformerless-power-supply

So if its not 40ma then what is it? from the chart on that site and all the calculations I run in the calculator for X I find online.  It is indeed going to be a small value what ever it may be. But if there is an error in calculation would be nice to know the specifics.

The formula to calculate the capacitor size is as follows:

C = I / (2 * Pi * V * F)

Where V is the mains voltage and F is the mains frequency.  The current I is the level being dropped down to.

So for a U.S. application needing 40ma we get:

C = 0.04 / (2 * Pi * 120 * 60)  =  0.88uF

That works.  So yeah, keep that formula in your head if you need to throw something together in a pinch.