What Happens if You Use the Wrong Size Capacitor? Is It Safe?

A motor will not have an even magnetic field if an incorrect-sized capacitor is installed. This will cause the rotor to hesitate in uneven regions. This hesitation causes the motor to become noisy, increase energy consumption, decrease performance, and overheat.

What Happens if You Use the Wrong Size Capacitor

The difference in capacitor sizes may be big enough to restrict the expected accuracy if the capacitor is part of a tuned filter. If it is used to reduce ripple in a power circuit, this slightly higher capacitor size may have no effect and may even be an improvement.

What Happens if You Use the Wrong Size Capacitor in a Motor?

Larger capacitors typically have larger voltage ratings and hence cool down faster. It could also be due to age (caps shrink with age) or manufacturing capability. In most circumstances, the physical size of the capacitor is directly proportional to the voltage rating. 

A motor will not run properly if the capacitor is not of the appropriate size. This is not to say that greater is better, because an overly large capacitor might increase energy usage. In both cases, whether too large or too tiny, the motor’s life will be limited due to overheated motor windings.

Does Size of Capacitor Matter?

No, as long as the capacitance and voltage ratings are the same, the physical size of an electrolytic capacitor is unimportant. A possible exception is if the switching power supply uses low ESR capacitors, in which case the sizes may change.

The performance of all capacitors is not the same. Using a larger cap is not always the best solution. The capacitor should ideally be sized for the amount of charge required to give transient current to the circuit that it is filtering or decoupling.

What Happens if You Use a Bigger Capacitor Than the Recommended One?

A too big capacitor can increase energy usage. If the motor is too big or too little, its life will be cut short.

Motor manufacturers test motor and capacitor combinations for many hours to find the most efficient combination. Replacement-start capacitors have a microfarad rating tolerance of +10%, but exact run capacitors must be replaced.

Can You Replace a Capacitor With a Higher µF?

You can replace electric motor start capacitors with µF or mF ratings equal to or up to 20% higher F than the original capacitors powering the motor. The replacement capacitor’s voltage rating must be equal to or greater than the original.

Can I Replace a Capacitor With a Lower µF?

Lowering the F value may cause the circuit to misbehave or even fail completely. The following are some of the effects that lowering a capacitor’s f may have on various circuits.

  1. By reducing the capacitance of a resonant circuit, you will almost likely modify the resonant frequency, rendering the system unusable.
  2. Reducing the capacitor’s f will affect the timing intervals, which may be beneficial or detrimental depending on the application’s requirements.
  3. Because the capacitor values are chosen specifically, this would have a substantial impact on the operation of an amplifier circuit.

It is not suggested to reduce the capacitance if it impacts factors such as tuning or timing in a circuit. Sure, reducing the F by a small degree may not seem like much of a difference, but these minor adjustments will add up over time.

Can I use a 7.5 UF capacitor in place of a 5 µF?

Yes, you may use a 7.5 capacitor for a 5. However, in most circumstances, other capacitor characteristics, such as voltage, as well as the application, govern it. When the capacitance in a capacitive circuit rises, the capacitive reactance XC falls, causing the circuit current to rise, and vice versa.

Can I Replace a Capacitor With a Larger One?

The performance of all capacitors varies. It is not always the greatest solution to use a larger cap. The capacitor should ideally be sized to provide the amount of charge required to provide transient current to the circuit being filtered or decoupled.

Because capacitors are never perfect, their resonance spots limit their practical frequency response capability. Larger capacitors respond well to DC signals, but tiny chip capacitors offer a far higher frequency response.


If a capacitor is larger, its charge/discharge rate will be slower. Smaller capacitors have higher resonance points due to their lower ESL and are thus better for high frequency bypassing. The design of the cap can help reduce ESL and hence increase high-frequency performance.

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