Few weeks ago, we were discussing about building ATX DIY bench power supply – in that way, we can use or convert Computer Power Supply to breadboard power supply with stable, regulated voltage. Before explanation, for that DIY work – as computer’s power supply is a ready to use solution for computer board, that negative DC Voltage, like -5 Volt are present. You will use only the positive DC Voltages for building ATX DIY bench power supply.
If you have not yet tried to build DIY bench power supply yet, definitely on telecom devices you noticed negative DC Voltage. What is Negative DC Voltage, Like -5 Volt? Normally in high schools we know only one type of voltage, is not it?
What is Negative DC Voltage?
Sadly, we are taught many thing of old concepts. Electricity is not exactly analogous to water. There is quite good unclear idea about ground (GND), Earth, Negative among those who read basics in high schools and landed to electronics works. Electrical energy does not flow inside the wires. Are you confused about what you read? There is one more. Electricity is not made of negatively charged particles called electrons. These are fundamental wrongs commonly taught. We practically run electromagnetic field inside the wires. If you think about electrophoresis, you will understand the gap of the wrongly taught hypothesis. That anode, cathode of electrophoresis is used as normal terminology for basic electronic components like LED.
Any electrical, electronic thing has at least two terminals – ‘positive’ or ‘+’ and the other is ‘negative’ or ‘-‘. This differentiates that “electrons enter” (+) from “electrons exit” (-). You know that a coil can store energy in the magnetic field and a capacitor can store energy as an electric field. But case of a circuit handling energy is complicated. Ask yourself where is Ground (GND) or Earth in a battery. Ground, Earth is where you keep your feet. There are technical wrongs in terminologies mixed with 200 years old concepts. Ground (GND) is a reference point in a circuit from which voltages are measured. Rather a return path to complete the circuit. It can also be really direct physical connection to the Earth. In some circuits negative is the same as Ground (GND) or Earth, but in some circuits that GND = 0 Volt and in other parts of the circuit there is a negative voltage that is below that 0 Volt. If you connect a multimeter between that Ground (0 Volt) and -5 Volt it will read 5 as absolute numerical value.
+10v +++ +5v
| | < Battery
+5v --- 0v
| | < Another Battery
0v --- -5v
You will understand the difference if you test with a DC motor.