problem in an circuit

[venkat46]

i found a circuit on internet i make circuit but it doesn't work properly i need some help please and i upload the circuit link on below

**broken link removed**

 

[KeepItSimpleStupid]

What doesn't work?

How easy is it to pull Q3, Q6 and the wire between D1 and R13?

 

[venkat46]

Total current path is not working when i just connect the BC327 the voltage through the collector shows zero only
even i switch ON the circuit the L1 & L2 glow at the time

and the Voltage circuit the out put is not varied
after i change the R8 in 1k resistor it varies some of the nearest value but its not accurate

 

[KeepItSimpleStupid]

That circuit is just odd. it does not appear to be a CC/CV power supply, but rather a CV Current limit with electronic fuse with no real way setting the value. It looks as if reset needs to be pushed to extinguish the overload light, so you should check that.

I have five supplies with a 723 in them. Voltage coming into the output terminals externally kills them. I have one that's currently dead. Parts, but no time.

I think, if you pull Q3, Q6 and the wire between D1 and R13 you will just have a voltage regulator. I suggest you start there first.

 

[venkat46]

OK then if you ill have any circuit for 0-30v 0-3a lab working power supply circuit with you ? without of the internet circuits

 

[KeepItSimpleStupid]

I actually have this **broken link removed** power supply.

A Powermate BPA 40D. I do have a paper manual. It's 40 V, 2A and uses two 723 regulators. I messed it up by reverse feeding it. The only issue I had/have is the I/V slide switch needing to be replaced. The fan runs all the time. It has course/fine for voltage and there is an engineering change order to change the voltage pot to 10 turn.

I also have a BelMerit PS501 that is 30 V, 3A with course/fine current controls and a digital switchable I/V meter. No schematic. It uses 723 regulators. It has indicators for CC/CV.

I also have both a precision 4 quadrant voltage and current source from Keithley. The current source is dead.

This handbook from HP is well worth reading https://www.davmar.org/pdf/HP-AN90B.pdf

I would probably prefer dual meters.

This https://www.djerickson.com/p1hack/ page is interesting.

he other one is a +5, +15, -15 supply that was part of some OEM system that used a 723 regulator.

In reality, you have to decide what you want. You have constant current/constant voltage and constant voltage/current limit. Most power supplies are of the constant voltage/current limit variety.

4-quadrant supples operate in all for quadrants like an amplifier. They can source voltage and sink current at the same time.

At the high end of stuff is the Source Measure Unit.

Then there is the "Electronic Load". It can operate at constant V, constant I, constant power and constant R.

I also have a "selectable" 0-32 v supply at 10 A that I picked up for $15.00. It's selectable because, you have to change the transformer tap depending on voltage. It's cool because a short on the output leads reduces the voltage to nearly zero. it's nominally set for 13.7 V.

You have to decide what you need.

This https://www.circuitspecialists.com/programmable-bench-power-supply-csi3645a.html is respectable, but no service info is provided.

 

[venkat46]

friend actually i am student now and i am not able to spend so much of money your followed circuits are seem little costly
And i want to learn and i want to implement on my own time period please help me to give some thing simple and efficiently

 

[KeepItSimpleStupid]

I gave you some resources. That was my intent.

My other intent is for you to remove the "components dealing with currnt" from what you have so far and see if you can get the voltage regulation to work. Add a fuse and you have a 30 V 3A voltage supply without electronic current limit.

 

[venkat46]

Ok then thanks for your help be in touch

 

[venkat46]

any one please say about of the difference between the TL081&mc34071

 

[audioguru]

TE="venkat46, post: 1223264, member: 257400"]any one please say about of the difference between the TL081&mc34071[/QUOTE]
I fixed the defective 0V-30V, 3mA to 3A Lab Power Supply at www.electronics-lab.com because many of its parts were overloaded and its transformer voltage was too low for it to produce 30V at 3A.

The datasheet for the TL081 shows a maximum allowed supply voltage of 36V but in the defective circuit it has 40V or more. The MC34071 is no longer available in the through holes DIP package but the TLE2141 opamp is available and both have a maximum allowed supply voltage of 44V.

The TL081 needs an additional 5.6V negative supply voltage but the MC34071 and TLE2141 opamps do not. One of the new opamps uses a negative supply supply voltage of 1.3V because its output must go negative to drive a diode to reduce the output voltage when it is regulating the output current.

The fixed circuit has its schematic, parts list and pcb designs in the forum at Electronics-Lab.

EDIT: In the Electronics-Lab Community Discussions yesterday there was a link **broken link removed**to a power supply that uses a switching regulator module from ebay that seems to be a low cost way to make an adjustable power supply that does not get hot.

 

[venkat46]

but in my city both mc34071 and tle2141 ic is not available it will make my concentration destroy what will i do i search the combination in web i don't have no result what should i do ?

 

[audioguru]

but in my city both mc34071 and tle2141 ic is not available it will make my concentration destroy what will i do i search the combination in web i don't have no result what should i do ?

Did you look at www.farnell.com and click on the flag of your country? They have warehouses all over the world called "Element 14".