Contents
What does a MOV do in an electrical circuit?
An MOV is a voltage dependent device which has an electrical behavior similar to back to back zener diodes. changes from a near open circuit to a very low value, thus clamping the transient voltage to a safe level. pulse is absorbed by the Varistor, thereby protecting vulnerable circuit components.
What does an MOV do?
The Metal Oxide Varistor or MOV is a voltage dependent, nonlinear device that provides excellent transient voltage suppression. The Metal Oxide Varistor is designed to protect various types of electronic devices and semiconductor elements from switching and induced lightning surges.
Where does MOV go in circuit?
The MOV is placed between the power supply mains and the circuit to be protected from the high voltage spikes is shown below. The resistance of the MOV is changed automatically based on the Voltage applied to the circuit.
How do you calculate MOV?
The current rating of the MOV could be twice that of the SMPS rating, meaning if the SMPS wattage is rated at 24 watts at the secondary, then the primary could be calculated as 24/285 = 0.084 amps, therefore the MOV current could be anywhere above 0.084 x 2 = 0.168 amps or 200mA.
How do I know if my MOV is bad?
Touch one meter probe to the free varistor lead and the other probe to the connected lead. Read the resistance on the meter. If it reads nearly infinite resistance, the varistor is still good. If it reads very low resistance, the varistor is blown.
When do resistors in parallel have the same voltage?
Branches with higher resistance will have a smaller proportion of the total current, and branches with lower resistance will have a larger proportion of the total current. Resistors are in parallel when they are connected between the same two nodes. It follows that resistors in parallel have the same voltage across their respective terminals.
How are parallel parallel circuit resistances calculated?
For resistors in parallel the equivalent circuit resistance R T is calculated differently. Here, the reciprocal ( 1/R ) value of the individual resistances are all added together instead of the resistances themselves with the inverse of the algebraic sum giving the equivalent resistance as shown.
How is the resistance of a varistor affected by voltage?
The above curve is the voltage and the resistance curve of a MOV, at the normal voltage the resistance is at its peak, but as the voltage increases the resistance of the varistor decreases. This curve can be used to understand how much resistance will be across your MOV at different voltage levels.
What happens when you add an additional resistor to a circuit?
What happens when you add an additional resistor next to the battery like so: Which part of the circuit is in series and which part is parallel? Is it possible to ascertain the resistance of this circuit at a glance? Or must one use Kirchoff’s Laws, set up a system of equations to find the equivalent resistance?