How to connect this Bench power supply to 220V AC step-down transformer to 12V AC output?

This circuit works normaly on +12V DC power supply:
Blueberry PSB400
Yellow wire: +12V, 12.0A, 144.00 W

The Incandescent Bulb, 6V/0.1A is connected to the Bench power supply output.

How to connect this Bench power supply to 220V AC step-down transformer to 12V
AC output?

When it is connected onto step-down transformer AC output 10-12V~ the R2 trimmer resistor resistor
is set to 10K.
The Bench power supply circuit is open and I just measure the voltage output
value.

When it is connected onto step-down transformer AC output 10-12V~ the R2 trimmer resistor resistor
burns up if I try to set R2 from 10K to 0R.

This does not happen if I connect this Bench power supply circuit into the
regulary DC voltage power supply +12V:
Blueberry PSB400
Yellow wire: +12V, 12.0A = 144.00 W

The Bench power supply circuit works normaly.
The Incandescent Bulb, 6V/0.1A is connected to the Bench power supply output.

DC example works normaly.
AC example - R2 trimmer resistor burns up.

The circuit diagram is taken from:

 

You have to include a rectifier and filter capacitor on the output of the transformer before connecting to the bench supply.
That's why it works using the DC power supply.

 

I think he is trying to tale a DC voltage regulator and use it to control an AC voltage. Not hap’nin.

 

I don't think so but the TS didn't read the third paragraph about the description of that bench supply

 

You have to include a rectifier and filter capacitor on the output of the transformer before connecting to the bench supply.
That's why it works using the DC power supply.
View attachment 300279

What a resistor value calculation should be used for R1 and R2 if I decide to connect it directly into wall outlet phase 220V AC?

 

What a resistor value calculation should be used for R1 and R2 if I decide to connect it directly into wall outlet phase 220V AC?

I think I should use 1N4007 rectifer diode?

 

What a resistor value calculation should be used for R1 and R2 if I decide to connect it directly into wall outlet phase 220V AC?

Please do not try that!
Doesn't work that way! Major explosion!
Didn't you read my post #2?
Required circuit:

 

What a resistor value calculation should be used for R1 and R2 if I decide to connect it directly into wall outlet phase 220V AC?

As I guessed. He thinks he can power that circuit with AC.

 

Please do not try that!
Doesn't work that way! Major explosion!
Didn't you read my post #2?
Required circuit:
View attachment 300286

I accept your advice. This should be very dangerous.

 

Are you just trying to power your DC adjustable supply from line voltage or are you trying to make an adjustable AC supply?