Electronics > Beginners
Homemade Transformer
gregariz:
By laminating the core you have significantly halted the flow of eddy currents an hence the source of heating/losses.
mishimaBeef:
Okay thanks everyone for all the replies I really am enjoying this community so far!
I guess my ambition seems a little far fetched and possibly misplaced and I realize that it is better to be safe than sorry. Perhaps I will commit my design to paper and it will stay there. I guess there are more interesting and safer things in circuit design than to have to worry about the electromagnetics of transformer design at such a dangerous electricity level. But thanks for the discussion, you have all given me something to think about.
By the way, how much power can be drawn from a function generator typically?
saturation:
Much less than < 1W. Most are current limited to 40-60mA in 50 ohms, and maximum tRMS voltage of about 4VAC, at 60 Hz sine, that's ~ < 0.24W.
--- Quote from: mishimaBeef on July 06, 2011, 02:24:36 am ---
By the way, how much power can be drawn from a function generator typically?
--- End quote ---
Zero999:
--- Quote from: mishimaBeef on July 06, 2011, 12:48:05 am ---I don't understand what all the fuss is about. Fusing the primary is a good precaution isn't it? Also, isn't the household wiring protected by a 15 A circuit breaker and then fuses downstream from that?
Why is wiring the secondary so much less trouble than wiring the primary exactly?
--- End quote ---
What if you don't use adequate insulation between the primary and secondary? Someone could be electrocuted when they touch something connected to the secondary?
The 15A breaker offers no protection against the transformer catching fire. If the DC resistance of the primary coil is 20 Ohms and you didn't use a laminated iron core, effectively creating a short circuit turn on the secondary, assuming the mains is 230V, the current would only be 230/20 = 12.5A but dissipation in the transformer will be 230*12.5 = 2875W which will cause it to glow red hot and catch fire.
A decent quality transformer bought from an electronics shop will have a laminated core, the correct number of turns on the primary, sufficient insulation between the primary and secondary and a thermal fuse or bimetal strip for protection against fire.
ipman:
Building a resistor is as simple as measuring with tester probes along a copper wire, stopping at desired value and cutting the wire. And that's a resistor! For bigger values, wind the wire on something which does not conduct electricity, but beware: this will increase the inductance.
A capacitor is not much complicated to produce, but not much.
Buutt ... you will be crazy if you connected those at mains voltage! That's why everybody is telling you to get an industrial one.
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