Further to my last post about using x rated capacitors,

Just wondered as I have note used a capacitor in combination with a
small transformer before, would there be a chance it form a tuned
circuit i.e. when would the capacitive reactance equal the inductive
reactance at 60 hz.

Need to know the inductive reactance of the transformer primary at 60hz.

Xl = 2 TT.f.l

Then f = 1/2TTsqr-root LC

Been a series tuned circuit the impedance would be very low at this
frequency and if this falls close to 60hz then the current may increase
substantially :-(

All this will probably be untrue as the inductance would need to be
large.

Unfortunately my calculations do no ring true when the inductance is 1
or higher the frequency seems to go up again instead of coming down.

So for the math experts what is wrong with my tuned frequency formula
when the inductance => one?  

_______________________________________
Roy
Tauranga
New Zealand
_______________________________________

-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf
Of Hopkins
Sent: Sunday, 15 May 2005 6:05 a.m.
To: 'Microcontroller discussion list - Public.'
Subject: RE: [EE] Block miniature transformer

Ok how about using an X rated capacitor to limit primary 230v current.
This will limit current with out the heat loses.

Capacitive Reactance	
	Xc = 1/2.TT.f.c
	f in hz
	c in farads
	
2.TT =	6.283185307
Freq =	50
C uf =	0.01
Xc Ohms=	318,309.89
Mains Voltage	230.00
Current =	0.00072
 

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