DIY

Regulated power supply for LM723 do it yourself

Adjustable do-it-yourself power supply unit for LM723 I welcome everyone today as promised we will consider a more powerful power supply circuit on the lm723 microcircuit, it turned out to be pretty hot.
A power supply is a rather necessary thing for every radio amateur, without it we will not be able to power different electronic circuits, but using batteries is not at all profitable.
Regulated power supply unit for LM723 with your own hands To begin with, let's look at the circuit itself, as I said earlier, it is built on the LM723 microcircuit, this is a universal voltage regulator, something like the LM317, and it additionally has protection against short circuit and overload. This microcircuit is installed in industrial laboratory power supplies.
Adjustable power supply unit for LM723 with your own hands The circuit also contains 5 transistors that will help increase the maximum output current. I must say right away that this circuit can give out as much as 20A at the output, but the author does not need such currents, and there is no such powerful power source, the maximum required 7-8A at the output is not more. In the original circuit, there are 2N3055 transistors and these were not available, so MGE13009 transistors will be used according to their characteristics, it is not bad enough for a current gain from 8 to 40 and a maximum collector current of 12A. But his big drawback is that he has a TO-220 case for linear circuits, he is not very suitable. It would be cool to take the KT827 transistors for this circuit, it will fit here ideally since it is a composite transistor and the current gain in it is very large and the dissipated power is about 100W.
 Do-it-yourself adjustable power supply unit for LM723 Power transistors will warm up quite well with high current or with a large difference in input and output voltage. The circuit is linear, therefore, the heat must be removed to the maximum so that the efficiency of our circuit does not fall. Do not forget to spread a thin layer of thermal paste on the transistors to improve contact with the heatsink.
Adjustable power supply unit for LM723 with your own hands The circuit also has a coupling transistor BD141, but KT961V will be used in terms of its characteristics, it is quite similar, the collector current is 2A here, it should fit perfectly. It acts as a driver for power transistors by this we will unload the LM723 microcircuit.
Adjustable power supply unit for LM723 with your own hands Also, you may have noticed 8 powerful 5W 0.1Ω resistors – R4, R6, R8, R10 serve to equalize the current through the transistors, and R5, R7, R9, R11 serve as a current sensor to protect against overcurrent. The current sensor input is legs 2 and 3 on the LM microcircuit.
Adjustable power supply unit for LM723 with your own hands We have already figured out the details and the diagram, now we proceed to the assembly. The whole circuit is soldered on a homemade printed circuit board, you can find the link to the archive in the description under the video.
[center] Adjustable power supply unit for LM723 with your own hands As a result, we get such a module, it remains only to test it under load.
DIY adjustable power supply unit for LM723 A 24V pulsed power supply unit with 10A current will be used as a constant power source. The circuit is linear and it is desirable to use a transformer with a diode bridge and a capacitor bank.
Adjustable power supply unit for LM723 with your own hands Putting together a quick test stand. The red multimeter measures voltage, blue current. The maximum output voltage turned out to be 21.7V at the input 24, and the minimum voltage is 4.2 V.
At a voltage of 12 V and a current of 3.4A, the circuit heats up and about 40W of heat dissipates on the radiator.
But the problem comes out when the load is disconnected the tension has risen sharply to the maximum and gradually returns to the original.
Adjustable DIY power supply unit for LM723 The problem was that there was enough capacitor at the input after they put this handsome K-50 at a voltage of 25V and a capacity of 33000Mkf after it the problem disappeared.
Adjustable do-it-yourself power supply unit for LM723 Now we need to take the load more powerful by as much as 6 Amperes at a voltage of 12V. The scheme was not tormented for a long time, since the radiator literally in 30 seconds heated up to boiling water. About 66W of heat is dissipated on the radiator.
This circuit needs a large heat sink, preferably with active cooling, or you can implement switching of the transformer windings, then the need for a huge radiator should disappear. Also, take better transistors in a large case, let's say TO-247, so the transistors pass more power through themselves. Thanks for your attention for now.

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