audioguru Posted November 29, 2009 Report Posted November 29, 2009 I have 60VA transformator (230 / 22VAC - 2,8A). Is that enough for original regulated power supply ( here )? How many ampers fuse I need for that transoformator on primar side?Thanks. A 22V transformer will allow a 23VDC output at max current. Use a bigger main filter capacitor because the original one is much too small.a 2.8A transformer will be overloaded when the output of the project is more than 2ADC. Quote
xsyt Posted November 29, 2009 Report Posted November 29, 2009 Two 2200uF/50V in parallel connection is okay? The transformer is that; http://www.neuhold-elektronik.at/catshop/product_info.php?cPath=131&products_id=3372I have the same wish as corsa, can anyone post the last mod. design PCB? Quote
Hero999 Posted November 30, 2009 Report Posted November 30, 2009 You're not listening, you need a 30V transformer capable of supplying 4.2A Quote
audioguru Posted November 30, 2009 Report Posted November 30, 2009 Why do you want to use an over-priced, tiny, low voltage, low current, low power transformator?We have posted the latest schematic and parts list hundreds of times on many threads here. Quote
xsyt Posted November 30, 2009 Report Posted November 30, 2009 For mod. version I'll buy another transformer. (for another project)Original version I need for two channel power supply. In that project I don't need really 3ADC output. That is the reason for low power transformer. And that transformers I already got it. Quote
audioguru Posted November 30, 2009 Report Posted November 30, 2009 Maybe you should use a simple LM350 adjustable voltage regulator.You could add a second one in series for current regulation. Quote
xsyt Posted November 30, 2009 Report Posted November 30, 2009 audioguru, but anyway I need the current limit. Quote
audioguru Posted November 30, 2009 Report Posted November 30, 2009 An LM350 plus one variable resistor makes a current regulator that can be in series with an LM350 adjustable voltage regulator.A current regulator is more accurate than a current limiter. Quote
redwire Posted November 30, 2009 Author Report Posted November 30, 2009 Hi Corsa, Here is the pcb in EAGLE for the board at the top of the thread. It is a double sided board because I had it produced at a professional shop. It is somewhat of a challenge to build double sided boards at home.Note that D2 and D3 need to be filled with a 1N4148 and D7 is not used for the latest version.Good luckEDIT: After opening board file in Eagle, hit Ratsnet to fill ground plane under R7PS-6.rar Quote
corsa Posted November 30, 2009 Report Posted November 30, 2009 Hi Corsa, Here is the pcb in EAGLE for the board at the top of the thread. It is a double sided board because I had it produced at a professional shop. It is somewhat of a challenge to build double sided boards at home.Note that D2 and D3 need to be filled with a 1N4148 and D7 is not used for the latest version.Good luckHello redwire, thanks a lot for this!! I'm looking for this a long time ago ;DIn really, this is not easy to make on home, i think... heheI will try 8) Quote
redwire Posted November 30, 2009 Author Report Posted November 30, 2009 Corsa, you may be able to use the Eagle file I posted to change the double sided pcb to a single sided board. This may require some jumper wires. Note that some of the traces are quite wide to handle large currents. Most are not. If you don't want to create your own pcb send me a PM. Quote
karthikeid Posted December 1, 2009 Report Posted December 1, 2009 hiwhat are the things to be checked before connecting the circuit to load...and i have used only 24volts 3amps transformer what will be the maximum power delivered to the output ??? Quote
audioguru Posted December 1, 2009 Report Posted December 1, 2009 hiwhat are the things to be checked before connecting the circuit to load...and i have used only 24volts 3amps transformer what will be the maximum power delivered to the output ??? The original circuit uses a 24V/3A transformer. Its max output is about 23VDC at 4.2A but the transformer will be overloaded very much.The transformer is rated at only 24V x 3A= 72VA.The original circuit is not calibrated properly to limit the current to 3A.The unregulated voltage is 34VDC and the transformer is trying to supply 34V x 4.2A= 143VA.The current should be limited to 72VA/34V= 2.1A then the transformer will be operating at its max rating. The max output voltage at 2.1A will be about 26VDC. Quote
karthikeid Posted December 2, 2009 Report Posted December 2, 2009 my psu seems to be not working there is no voltage variation and i have used tle2141 opamps....what should i do.... ??? :( the led is glowing without any load....i have posted the circuit diagram and the pcb made by me...Ultiboard0000002323.pdf Quote
audioguru Posted December 2, 2009 Report Posted December 2, 2009 my psu seems to be not working there is no voltage variation and i have used tle2141 opamps....what should i do.... ??? :( the led is glowing without any load....i have posted the circuit diagram and the pcb made by me...U3 turns on the LED and makes the output voltage as low as 0V.With a 10M input resistance meter, measure its input voltages with the current pot set to max and no load. Use the negative wire of C1 for the negative meter lead. Quote
karthikeid Posted December 2, 2009 Report Posted December 2, 2009 the wiper at one end of the pot measures 4.7V and at other end -0.6V input voltage of U3....next hat should i do.. Quote
audioguru Posted December 2, 2009 Report Posted December 2, 2009 Hi Karthikeid,The current adjust pot should have a max voltage of only +1.7V so your +4.7V is much too high. It comes through a voltage divider from the output of U1 which should be +11.2V. Measure it.But the LED should not light because the output of U3 should be high. Measure it.Also measure the voltage at C1.Which version of the circuit did you make? Quote
karthikeid Posted December 3, 2009 Report Posted December 3, 2009 i have made some mistakes in the pcb and i have corrected it now the led is not glowing and voltage at the current is 1.8, the output of U1 +11.4...but even i am not able to vary the voltage... :(at c1 it is 28.6Vhi redwire can u post the pcb u made??? Quote
audioguru Posted December 3, 2009 Report Posted December 3, 2009 The voltage adjust pot gives from 0V to +11.4V to U2.U2 is part of the output amplifier that has a voltage gain of 3.08. Quote
karthikeid Posted December 3, 2009 Report Posted December 3, 2009 when the U2 will measure zero... what should i check it is not working... Quote
audioguru Posted December 3, 2009 Report Posted December 3, 2009 Check that the voltage adjust pot gives from 0V to +11.4V to the input of U2. Quote
karthikeid Posted December 3, 2009 Report Posted December 3, 2009 yes the input voltage at U2 varies from 0 to +11.4V....then what should i do... Quote
audioguru Posted December 3, 2009 Report Posted December 3, 2009 U2 is an opamp that drives two emitter-followers. They have a voltage gain of slightly more than 3.What does the output of U2 do when you vary the voltage pot? Quote
karthikeid Posted December 3, 2009 Report Posted December 3, 2009 the output of U2 reads 28.5V when in input of U2 above 0.5V and output U2 reads zero at input is zero Quote
redwire Posted December 3, 2009 Author Report Posted December 3, 2009 Hi karthikeid I posted my pcb file a few pages up but here is the link: http://www.electronics-lab.com/forum/index.php?topic=19066.msg89170#msg89170 Quote
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