A negative voltage simply means that there is a potential difference between two points in an electric circuit. This potential difference can be caused by either a direct current (DC) or an alternating current (AC) source. A negative voltage is the measure of the electron potential or energy.
Zero volts could be any point in the circuit, but to be consistent it is normally the negative terminal of the battery or power supply.
The polarity of a voltage is indicated by “+ ” and “-” signs on a circuit diagram. The “+” sign is at the point where the voltage is assumed to be higher, while the “- ” sign is at the point which is assumed to have the lower voltage.
A negative voltage is a measure of electron potential or energy. It is measured in volts and has the symbol “-V.” The higher the negative voltage, the more potential energy or electrons are available. This can be useful in electrical circuits to move electrons from one place to another.
The negative reading may indicate that your battery is bad, even if recently replaced. You'll find that this is the case if you consistently find the charge starting at 12.5 volts before quickly dropping, and remaining, below 8 or 9 volts. This can be a sign that you need a new battery.
A battery is a very quick negative voltage source. In a 9V battery, there are two terminals: anode for positive voltage and cathode for negative voltage. As most devices are designed for positive voltage supply, the negative terminal serves as a ground.
A common way to generate a negative voltage has been to use an operational amplifier (op amp) to invert the output of a positive precision voltage reference. This approach typically requires a positive reference, the op amp, and two supply rails to generate the negative output.
A negative voltage simply means that there is a potential difference between two points in an electric circuit. This potential difference can be caused by either a direct current (DC) or an alternating current (AC) source. A negative voltage is the measure of the electron potential or energy.
Similarly, a positive voltage causes conventional current to flow from the positive node to the reference node, and a negative voltage causes current to flow from the reference node to the negative node.
Electrons have negative charge, and hence where they come from has negative relative voltage (since energy here is positive).
The polarity of the voltage drop across any resistive component is determined by the direction of electron flow through it: negative entering, and positive exiting.
Once a voltage is applied to the material, the electrons move from the negative towards the positive. Remember that electrons have a negative charge. Since the negative side of the voltage source repels the electrons, they move away from it and head towards the positive side, which they are attracted to.
While current flows from the positive to the negative terminal, electrons flow from a negative to a positive direction. A resistor consumes energy regardless if a charge enters the component as positive or exits as negative. Voltage usually drops across all passive elements, such as resistors.
In contrast, Zero-Volt means that all of a battery's stored energy has been discharged, well below the normal operating voltage range. At this point, a lithium ion cell is rendered totally inert. A cell or battery in a Zero-Volt condition poses no risk of fire, explosion or electric shock.
Because you're measuring the voltage at a node with respect to that same node, i.e. with respect to itself. So, the potential difference (a.k.a. voltage) between those nodes is zero because it's the same node. It's like measuring the length or distance from a point to that same point: it's zero.
Why does the terminal of a battery have negative voltage? Referenced to the positive terminal, the negative terminal is negative. That just means that electrons flow out from that terminal - it “supplies” electrons, which have negative charges.
A negative value of current simply means that positive current actually flows in the direction opposite the arrow label. A negative voltage drop means that the + label is actually at a lower voltage level than the - label.
A DC voltage is always positive (or always negative), but it may increase and decrease. Electronic circuits normally require a steady DC supply which is constant at one value or a smooth DC supply which has a small variation called ripple.
-12v is 12 volts below ground. We don't use voltage below ground much in digital electronics (indeed, exposing any arduino pin to a voltage below ground will damage it), but it's quite common with analog stuff. It's not unusual to see opamps, comparators, or digipots that have voltages both above and below ground.
Is the negative terminal the same as ground? Yes in single power supply. For e.g. battery negative is connected to ground.
To block negative supply voltages, system designers traditionally place a power diode in series with the supply. However, this diode takes up valuable board space and dissipates a significant amount of power at high load currents.
To say you have a voltage of -5V at point B means that 'ground' is 5 volts more positive than point B. The sign just tells you the polarity of the voltage, with respect to the ground node.
A power supply of 5V, with the negative pole as the reference "zero point", the positive pole is +5v; with the positive pole as the reference "zero point", the negative pole is -5V.
If your multimeter reads a negative voltage, it means that your leads are in the wrong position. To fix this, reverse the order of your leads. Your black lead should go where your red lead is. Your red lead should go where your black lead is.
Another such device that uses negative voltage is an op amp circuit, since it's composed of many transistors. Many op amps function off of a dual power supply. One lead of the op amp receives positive voltage and the other receives negative voltage. Dual op amps need both positive and negative voltage to work.