Good day, we have a project that is called diy power supply and I follow this circuit on YouTube (

), i already follow his circuit but the problem is no output,and the current did cannot be shown in digital voltmeter and ammeter,what should I do?.

 

Welcome to AAC!

we have a project that is called diy power supply and I follow this circuit on YouTube

That isn't a voltage regulator. There's no feedback.

i already follow his circuit but the problem is no output,and the current did cannot be shown in digital voltmeter and ammeter,what should I do?

Post the voltages at important nodes.

Your schematic isn't drawn in the "standard" manner. I'll redraw and post in a few minutes.

Assuming the 40V input is well regulated, the output voltage will change depending on load. Have no idea why they used the rectifier diodes.

 

Disconnect your digital ammeter. Don't try to measure current just yet.
Do you have a voltmeter or DMM (digital multimeter)?

 

Had to look through dozens of voltage regulator circuits to find a reasonable one:

https://electronicspost.com/series-feedback-voltage-regulator/

You'd add current limiting by inserting a sense resistor in the output (before the resistor divider).

This one has current limiting, but should have Rs for the diode (and I'd use a zener):

https://freecircuitdiagram.com/2271-discrete-voltage-regulator/

 

This circuit, as shown in the schematic, is NOT the same circuit shown in the video. For starters, the video shows a 33 ohm, 5W resistor on the emitter, that is nowhere to be seen in the schematic.

Additionally, that ElectroProject YT channel is full of absurd circuits. He appears to throw in components to see what happens, but really doesn't understand what is going on. That is the reason he never posts schematics and puts music instead of a technical explanation.

For instance.... How does the green pot actually adjust current, without any current sense feedback? It is nonsense.

 

Welcome to AAC!
That isn't a voltage regulator. There's no feedback.

Post the voltages at important nodes.

Your schematic isn't drawn in the "standard" manner. I'll redraw and post in a few minutes.
View attachment 323659
Assuming the 40V input is well regulated, the output voltage will change depending on load. Have no idea why they used the rectifier diodes.

Thank you for helping me, is this circuit working?

 

Disconnect your digital ammeter. Don't try to measure current just yet.
Do you have a voltmeter or DMM (digital multimeter)?

Yes in the picture, I already disconnect it, i just use multimeter

 

Thank you for helping me, is this circuit working?

No. It's just a redraw of what you posted. It isn't a voltage regulator circuit and it doesn't have current limiting either.

The second circuit I posted is a regulator with current limiting.

 

No. It's just a redraw of what you posted. It isn't a voltage regulator circuit and it doesn't have current limiting either.

The second circuit I posted is a regulator with current limiting.

Thank you for helping me, i want to follow the one you send but the problem is some components are not available. THANK YOU

 

i want to follow the one you send but the problem is some components are not available

Which components?.

 

I am confused. Was the assignment to make that circuit from youtube work? If not, what is the assignment?

 

Welcome to AAC!
That isn't a voltage regulator. There's no feedback.

Post the voltages at important nodes.

Your schematic isn't drawn in the "standard" manner. I'll redraw and post in a few minutes.
View attachment 323659
Assuming the 40V input is well regulated, the output voltage will change depending on load. Have no idea why they used the rectifier diodes.

Hi,

Usually the diodes or zener are present to set up a quasi-voltage reference source. That sets the output voltage to a value that stays roughly the same even with load or input voltage change (transistor as voltage follower).
This looks more like a cross between a voltage regulator and a capacitance multiplier. That would be used to smooth the input if there was ripple and not as much to regulate the output voltage value.