It's not reluctance but reactance.Originally Posted by DMW
Both capacitors (Xc = 1 / (2 pi F C) and inductors (XL = 2 pi F L) have reactance. If you have an inductor and a capacitor in series the total reactance is de difference of them (Total X = XL - Xc)
(The Reluctance is used in magnetic circuits)
E Cerfoglio
Buenos Aires
Argentina
ops yes i did know its reactants, I must of chosen the wrong one without thinking when dong spell check.
edit
I thought the total reactants of L/C was:
square-root(Xc^2 + XL^2)
Like Pythagoras theorem
Or is that something else?
Last edited by DMW; 29th February 2008 at 09:30 PM.
Not, if you have a capacitor, an inductor and a resistor in series, then the impedance (Z) isops yes i did know its reactants, I must of chosen the wrong one without thinking when dong spell check.
edit
I thought the total reactants of L/C was:
square-root(Xc^2 + XL^2)
Z = square-root(R^2 + (XL - Xc)^2)
(or, using complex numbers, Z = R + j (XL - XC), where j is the square root of minus one)
E Cerfoglio
Buenos Aires
Argentina
Of course its in converting from rectangular to polar form.
230 Volts LED
I have posted a schema a while back under 230 Volts LED with photo's.
I have used this succesfully for nearly 20 years in industrial metering and indication circuits on power systems 230 / 240 Volts 50 Hz.
D1 - 1N4007
D2 - 1N4148, 1N914
D3 - High efficiency LED
R1 - R2 - 33 or 39 khm: 1 Watt resistor
D1 assisits in reducing the power dissipation in R1 and R2 to 0.7.
To reduce flicker if it bothers you use a bridge rectifier as already suggested.
There are more ways to get to Rome.
Electricity, Electric clocks, Meters and Trains are great.
Please don't sent me private messages, I will not answer them.
The questions asked can be discussed in the open forums.
http://www.youtube.com/user/RODALCO2007 some interesting electrical stuff to watch.
My Bad
Thanks DMW... I need to relearn what Xc is and how to apply it.
Actually that's not true I believe [for the first diagram]
The 10M has little effect on the circuit, you see capacitors have a resistance to low frequencies, this is called reluctance rather than resistance because unlike resistance no power is dissipated in the capacitor.
The Formula shown below determines the reluctance for a capacitance.
Xc = 1/(2 * Pi * F * C)
Xc = 1/(2*Pi*50*220nF)
Xc = 14.4Kohm
This is in parallel with 10M, because 10M is so high it makes little difference to the resistance.
14.4K + 1K because its in series with the 1K resistor is
15.4K
current = 230 / 15.4 = 15mA
Seems a little low to me.
Edit:Whops I was using RMS value
root(2) * 230 = 425V
425 / 15400 = 21mA.
Thats better
Wayne2056
Another option is to just use a bipolar LED which will produce no flicker and won't require a reverse parallel diode.
I do not answer private messages asking for help because no one else can: benefit from advice I may give or correct me if I'm wrong.
Please ask on the open forum if you have a question and I'll be happy to help, if I know the answer.
better yet just stick the LED in a diode bridge if its a HB, Only junk die come in bipolar LEDs until you get to the expensive stuff that they proceed to charge even more for.
thanks all to help me with suggestions.
i'm fully stupid about the hitek laws.
but i impressed with rodalco's idea.
dear rodalco, what difference on effecincy LED and general LED?
mamun2a, dhaka, BD
'if u cant beat him then join him' I always say...
Many years ago I also used this principle to make a led light up just for signalling, no harm in that.
But today my interest is on LED lightning, thus there may be a legal harm. As I understood the effect of the capacitor it causes a phase shift (sorry if I use wrong terms, im a bit rusty on this)
Now the effect of this phase shift is that voltage & current does not follow each other and thus no components are overloaded.
But that kind of circuits may also cheat the power meter from the electricity company, and thus they are illegal. The same effect is seen on neon tubes where a capacitor is required for the metering to be accurate.
Also a similar effect is seen from switchmode power supplies in eg computers, where the cheap power meters cannot measure the power consumption of a computer. I don't know why the power meter from the electricity company can handle computers though.
But besides all that, what is the more power effective, a switchmode power supply or a capacitor? The switchmode can do 80-90% efficiency today. But it is quite expensive. Cheap transformer based power supplies do not go above 50% efficiency.
Thus using capasitors could be very interesting. Especially now when all the Christmas lightning comes up again.
Please Help
What if i need to have 4 LEDs in series or in parallel ??
With one 2V LED operating from 220V then its current is 21.8mA with a 10k ohm resistor.
With four 2V LEDs in series operating from 220V and with a 10k ohm resistor the current will be 21.2mA and they will look the same as the one LED.
LEDs should not be connected in parallel. They are not exactly the same so one will hog a lot of the total current and burn out. Then the remaining LEDs will have more current and they will quickly burn out.
Uncle $crooge
you mean to say that, if i connect 4 LEDs in series using the same circuit there would be no change required in circuit ?
the glow of each LED will be same(as when a single LED was used) or will 1/4
I showed the calculation for the current in one LED to be almost the same as the current in 4 LEDs because the voltage is so high that there is very little difference in the current. Then there is very little difference in the brightness.
If each LED is 2V and if the supply is only 10V then one LED will have a current of 20.5mA with a resistor of 390 ohms and four 2V LEDs in series and with a 390 ohm resistor will have a current of 5.1mA (one-quarter of the current for one).
Uncle $crooge
Emergency LED Light with a Battery
hi,
I have build a lot of lights of this kind using a 2.2mfd 400VAC capacitor in series with a bridge rectifier, and it has got ample power to trickle charge the Battery which is 6V 7AH, and it can sustain 104 Leds (5mm White LED) for 4 hours.
some people might think this a hoax, but they dont live in a country which has got 14 hours power outages every 24 hours. So I think I am more desperate than most of you to make the dream come true with a Solar Cell for a Light without mains supply.
Insider
Kinetics Automation
fahimbaig2@gmail.com
Reply With Quote
