Contents
How can you trim the output voltage of a power supply?
Most often users are able to trim the output voltage of a power supply by adding external components, adjusting a PCB mounted potentiometer, or applying an analog or digital signal. Power supplies with the ability to trim the output voltage are typically used for two reasons:
When does an ATX power supply become obsolete?
A product that is often built to a very high standard and which will give years of faithful service, yet which has a life of only a few years as the PC of which it is a part becomes obsolete. Over the decades it has evolved from the original PC and AT into ATX, supplying an ever-expanding range of voltage rails at increasing power levels.
Is the tl494 a switch mode power supply?
The TL494 is a switched-mode power supply controller designed to work in a variety of configurations and manufactured by multiple semiconductor companies. The basic operation of a switch-mode power supply is fairly straightforward, and ATX supplies have very few deviations from the norm.
Can a motherboard be used as a power supply?
You shouldn’t need an explanation of how these could be reused, if you don’t mind a bit of steel drilling and your project case being obviously that of a PC power supply then they are very robust enclosures. The same goes for the wiring loom of motherboard and disk power connectors, a handy source of medium-sized hook-up wire.
Can a trim pot be adjusted under microprocessor control?
A manual trim pot may be used, but it is often large and can suffer from reliability problems due to wear associated with the manual adjustments; furthermore, it cannot be adjusted under microprocessor control.
How does a potentiometer change the output voltage?
The center tap where they join is the new output voltage, which is at the ratio of the two resistors: You can replace the two resistors with a potentiometer in the exact same arrangement. The wiper of the potentiometer is the center tap of the voltage divider, and the two resistances between the wiper and either end are the two resistors R1 and R2.
Do you need a regulator for a potentiometer?
So you must use a regulator to get a constant voltage out. In order to achieve the ability to adjust the output voltage with a pot, you will want to use something like the LM117.