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mendimano
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Posts posted by mendimano
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I have 4 high power SCR (silicon controlled rectifiers) im intend to use them as controlled rectifier bridge,
at internet i have found the schematic which seems to me as ok, but some components dont have values,
can any one advise me and help.
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Hi seb,
If you have carefully readed the thread then you will have answers to all of your questions :) -
It is perfect for that.
;D -
Hi everybody i hope someone can help me to identify and eventualy send me datasheet for this component
wich i have removed from an old industrial inverter ( 4 of them), the component has this marks on it:
AEG T 45 F1100 EFC-2?LO ( one character aint fully readable i marked with ?) and havs an SCR or THyristor symbol on it.
Very best regards.
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Hi red baron , try to replace the R17 from 33 Ohm 1/4 watt rezistor to 47 Ohm 1/4 watt rezistor.
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Thanx for help Hero999, i wonder if is it posible from you to post a scetch shematic of this.
The transistors driving the LEDs form a divide by two counter which changes state on every clap. The counter is triggered by a pulse AC-coupled to the emitters via a 100nF capacitor. All you need to do is add another pair of transistors in the same divide by two counter configuration before the transistor which drives the relay.
It would make it easier to explain if all of the components were numbered i.e. Tr1, Tr2, C1, C2 etc.
Here are a couple of links to other websites showing a similar circuit.
http://www.electronics-tutorials.ws/waveforms/bistable.html
http://ch00ftech.com/2012/07/10/transistor-clock-part-2-prescaler/ -
Hi red baron, congratulations for a good work, im posting some pictures of power supply 5 ampers version that i have build it one year ago, it is working perfectly and acuratly thanx to audioguru and redwires tips schematics and parts list, i have used 3 power tranzistors MJ11016 and 10 amp 30 volt transformer, i have tested with 30 volts 8 ampers load it worked without any problems, some tests and measurments you will have to do it in your own becouse it is imposible to see from here what is wrong with your power supply,
but anyway im encouraging you to finish your power supply .
very best regards
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Hi neba 3939, this is an intresting project, i dould like to try this project, is it posible from you to post the values of components, for diodes for example.
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Well Tompa it is dificult to help you from here, maby you should check your output tranzistor/tranzistors,
i watched the video and your P.S worked then just fine, check for any wires soldering joints wich might broaken during the instalation of your P.S to enclosure. -
Hi evererybody, i have found this project on internet, it seems intresting to me,
im calling everybody to discus about this project.
thanx
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Let me inform you that i have changed the value of R17 from 33 Ohm to 47 Ohm, and now the warning LED of an current limiter does not light when there is no load, thank you Audioguru.
Your video shows that the warning LED lights when there is no load and the current-setting pot is turned down which is wrong. It is due to an input offset voltage of U3. Increase the value of R17 (it is now 33 ohms) to maybe 47 ohms or 68 ohms until the LED does not light when the current-setting pot is at minimum. -
But what about if you want to charge a batterry with thats say for example 12 Volts and 2.5 amps....when battery draws 5 amps...and you want to limit the current for a beater charging...when the gurrent limiter is activated...you cant regulate the voltage to 12 volts....
It draws 5A at 12V when hot and it draws maybe 50A when cold.
The moment that you connect it then it will try to draw 50A but the current-regulation will limit its current to only 3A by limiting or reducing the voltage.
If you turn the current-setting to maximum and the voltage to zero, connect the light bulb then slowly turn up the voltage it should work up to maybe 10V at 3A.
Your video shows that the warning LED lights when there is no load and the current-setting pot is turned down which is wrong. It is due to an input offset voltage of U3. Increase the value of R17 (it is now 33 ohms) to maybe 47 ohms or 68 ohms until the LED does not light when the current-setting pot is at minimum. -
Thanks for your tips gogo, seems reasonable to use 1% resistors for more accuracy,
ill try that and i hope it will work beater then,
and happy new year -
gogo im refering to this project
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I brought a kit from Velleman which was based om the ICL7107 and I found that this gave unstable readings and could never cure the bouncing of the readings, May be this is why they stopped selling it ?
So in the end I decided to design and build my own based on the MAX7219 and PIC16F876, This gives accurate and stable readings and is now used in my Velleman PSU 0-30V 0-10A, I used ISIS to simulate it to get everything working(Picture attached) and then designed and built the PCB for it.
I like the idea of LED'S because where my PSU sits at the back of the bench I don't have to lean forward to see the LCD version. Plus I use the green version which is better
hi Picmaster is it posible from you to post the schematic and pcb of this volmeter of yours? ( PIC based) -
There are two versions of the old ICL7107 IC. The newer version ICL7107S has improved Stability.
The LED display draws up to 224mA through the IC which heats it a lot and causes it to drift.
It needs an additional -5V supply but you don't say how you produced it.
The L7805 regulator must have the two small capacitors shown on its datasheet. It needs a minimum input of +7V so the average rectified and filtered voltage must be more, depending on how much ripple is produced by the filter capacitor.
If the rectifier is full-wave then a 1000uF filter capacitor reduces the ripple to 1V peak. The transformer should be 8VAC or more at 500mA.
Im using the the ICL7107 CLP version,
i have produce the -5 volt with IC ICL7660 -
Yes i have build it , and according to IC datasheet, actually i have build it 2 of them one will ICL7107 Maxim Dallas production and one with INTERSIL ICL7107 they are both working good as long as I'm supplying them with 9 volt battery , only I'm having problem when I'm supplying them through transformer , i can say from my experience that the Intersil IC is working more stable when I'm feeding them through transformer, could it be the problem with smoothing the AC current?
any ideas and suggestions about the rectifier bridge and capacitor (value), and how much should be the voltage of AC voltage of secondary of the transformer? since I'm using the L7805 regulator for voltmeters. -
Yes that's correct i have used the 100 microfarad capacitor,
i will try to use 1000 microfarad capacitor instead, thanks for advice -
I have built the voltmeter and it works O.K when I'm supplying it with 9 volt battery, but when I'm supplying it with 7,5 volt transformer and a rectifier bridge with 4X1N4007 diodes as a rectifier bridge and 100mF capacitor the last digit is going up and down, in other words voltmeter becomes unstable, any ideas and sugestions??
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I agree with you guru, ( you got a good point with working ina a dark ;D) but i have only 7 segment LED displays, anyway thank you very much for your help and advice
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The voltmeter project still has a lot of errors. Look at the datasheet of the voltmeter IC for corrections.
I think the voltmeter must be powered by a power supply that is separate from the power supply that it is measuring.
Dear guru my power supply transformer has a 2 pair of windings 15-0-15 volts (30 volts 10 amps) and
7.5-0-7.5 volts ( 15 volts and 2 amps) I'm intend to use this second winding to supply the LED voltmeters ( with rectifier bridge 4X 1N4007) also in a circuit that I'm going to use is an ICL7660 as a negative voltage converter (-5 volt). Please see attached schematic and PCB layout, i think until now this is the best and modified schematic, i hope doesent have any errors. -
Hi, im intend to build 2 LED voltmeters according to the schematics an PCB posted by M.P, i will use to measure the voltage and curent of Power supply wich i have build acording to the schematic at this site and modified to 0-30 volts 5 amps version, please if anyone can give me some calcuations for resistors value im intending to use 0.27 ohm resistor as a shunt to measure the current, ( R7 of P.S)
i have attached the PCB and schematic in eagle format of LED voltmeter. can someone tell me how much should be the value of R3 for 0-30 volts and how much sholud be the value of R3 for voltage 1.35 volts wich i have calculated for voltage drop across the 0.27 ohms resistor sow my panel voltmeter shows 0-5 amps current flow of P.S -
And what about R15 ? where is placed this resistor? in my schematic i dont have R15.
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Hi Florian Leech,
You have a very old parts list (about 5 years old) that does not match the latest schematic (about 1.5 years old) you found.
The latest parts list was posted on this website somewhere hundreds of times.
The zener diode and calibration trimpots do not have numbers yet.
With a current of 3.0A then R7 (0.47 ohms) dissipates 4.23W. A 5W resistor will be extremely hot so use a 10W resistor. I have never seen a 9W resistor but it will be fine.
The calibration trimpot's value and the resistor in series with it were selected with 0.47 ohms for R7.
The latest parts list uses TLE2141 or MC34071 opamps.
I fixed the original project that was a mess of errors, did not work properly and was not reliable.
Dear Audiguru can you tell me is this changes that you have posted in a latest parts lists ( R1=2.2Kohm , R11=27Kohm, R15=100Ohm, R18=33Kohm, R22=3,9Kohm)
are aplicable for 5 Ampers version of power supply
old values for this rezistors are ( R1=3.9Kohms, R11=10Kohm, R15=(there is no), R18=20Kohm R22=1.2Kohm)
0-30V Stabilized Power Supply
in Projects Q/A
Posted
Hi imester, nice work by the way, can you tell me where did you find voltmeter and ammeter with decimal point accuracy? or did you build yourselfe,
and can you post any links to buy those voltmeter and ammeters?