In this article we will deal with stabilization using integrated circuits, in our case positive 78xx circuits. A stabilizer is a component that stabilizes the output voltage when the input voltage changes or when the load current changes. We can simply say that the required voltage (5V, 12V….) Is compared with the supplied voltage. So if I have a stabilizer with an output voltage of 5V and I supply 12V to its input, then the comparison voltage will be Upor = Uin-Uout => Upor = 12V-5V => Upor = 7V. The output voltage will therefore be Uout = Uin-Upor => Uout = 12V-7V => Uout = 5V. These operations are taken care of by the appropriate connection of components inside the stabilizer.
More information in this link: https://en.wikipedia.org/wiki/Voltage_regulator
In the stabilization circuit diagram, we first notice two filter capacitors C1 and C3. Filter capacitors serve as short-term energy sources when the load current of the circuit changes rapidly. Before the source responds to this change, the capacitors discharge and partially compensate for the short current drop. The values of these capacitors are given by the manufacturer, it is true that the capacitor behind the stabilizer is approx. 10 times smaller than before the stabilizer.
The Graetz bridge consists of 4 diodes 1N4007, the choice of filter capacitors depends on the current consumption of the connected equipment. They should not be unnecessarily large, nor small. In my case, the board will be used to power microprocessor applications, so I chose smaller capacitors (C1 = 220uF / 63V, C3 = 10uF / 16V). The voltage of capacitor C1 should be at least 35V, as the maximum voltage at the input of the stabilizer can be up to 30V. Capacitor C2 is used to filter noise and interference in the line. The stabilizer is equipped with a cooler, which cools the stabilizer without any problems when taking 1A.
Printed circuit board:
Placement plan and PCB are at 1:1 300 dpi (How to print a PCB design can be found in the post How to print PCB design). Real size PCB is 82,5 x 17,5 mm.
|C1||electrolytic in text|
|C3||electrolytic in text|
|IO1||78xx (05,09,12,15,24 in text)|
|X1,X2||screw terminal for PCB, RM=5mm, 2 pin|