Thanks for the help.For starters, put a bigger transformer, one that can deliver 3A and more.
Thanks for the reply.A 3A transformer is not large enough.
You need to derate the transformer due to the high peak RMS currents that a rectifier-capacitor supply draws, so for 3A DC, the transformer should be rated for at least 5Arms.
Q1 will also need a hefty heat-sink that can dissipate about a 100W.
Thanks for the help guys.Any other advice?You need a 5amp transformer, a bridge rectifier 5amp, and an heatsink on the transistor..
It's due to the high peak currents drawn by the rectifier-capacitor.Actually i don't understand what does 5Arms mean?
"Since the RMS value is proportional to the square of the current..."It's due to the high peak currents drawn by the rectifier-capacitor.
Since the RMS value is proportional to the square of the current, the high peak current has a much higher RMS value (causing heating in the transformer windings).
Transformers are rated for RMS current.
Power is proportional to the square of the instantaneous current (through a resistive load)."Since the RMS value is proportional to the square of the current..."
That doesn't sound right.
Not true.Also, if the transformer is rated for RMS current, it would appear that 5A rms is sufficient for 5A DC.
Absolutely not."Thus RMS is proportional to the square of the current".
Above statement is absolutely false.
Bigger diodes. The 1N400x series is rated for 1 A continuous DC or RMS AC current. For a 3 A output current, you need a minimum of 5 A rated diodes. 10 A would be much better for long term reliability.Any advise from experienced engineers. Thanks
That proves nothing other than the transformer will deliver more RMS current than its rating since transformers don't limit their output to the RMS rating.it is spec'd at 2.5A rms and delivers 2.7A at 13VDC in a bridge rectifier circuit with capacitor filtering.
Ac voltage and current are specified in rms values..after rectification and filtration they tend to go higher in magnitude and direction cause the waveform tends to attain maximum amplitude..so to my own opinion if a transformer is rated 2.5A rms after rectification it should be able to deliver more than that..althouugh I Understand perfectly what u meant by the transformer burning out since there is no limiter there..No one is talking about overheating the transformer.
In the example I have shown, the transformer is designed to deliver 12.6VAC @ 2.5A
When asked to do so, it did and it did not burn up. And it delivered 13VDC @ 2.7A.
As far as I can see, 2.5A rms was sufficient for 2.5A DC at the rated voltage.
by Duane Benson
by Duane Benson
by Aaron Carman
by Aaron Carman