Most of us take our phone chargers for granted – until something unusual happens. How about the issue of phone charger making high-pitched noise…
This sound can be annoying, but is it more serious than that?
In this mini guide, we’ll explore why chargers make high-pitched noises. What causes it on a technical level? When might it signal a safety risk? And what you should do if your charger starts making this noise?
Skip to:
- What is the noise?
- Causes of high-pitched charger noise
- When is it normal
- Phone charger making high-pitched noise: Warning signs
- Safety tips
What is the noise
When you hear a faint, high-pitched sound coming from your phone charger, you’re likely hearing the switching frequency of the power conversion circuitry inside the adapter.
Most modern phone chargers are switch-mode power supplies (SMPS) – compact, efficient circuits that convert the AC power from your wall outlet into the low-voltage DC power your phone can use.
These circuits operate at high frequencies (typically between 20-100 kHz), often well above the range of human hearing.
However, under certain conditions, parts of the charger – especially transformers, coils, or capacitors – can vibrate slightly. When these vibrations resonate, they can create audible sounds in the 10-20 kHz range, which the human ear perceives as a high-pitched whine.
So, while the sound might be irritating, it’s usually not dangerous by itself; it’s simply an acoustic byproduct of electrical components doing their job.
Causes of high-pitched charger noise
Not all noises are created equal. Understanding the possible causes helps determine whether your charger is just noisy or potentially unsafe.
👉 Vibration of internal components
The most common cause is coil whine, a phenomenon where inductors or transformers vibrate due to alternating current passing through them. The magnetic fields cause the tiny copper coils or ferrite cores to move slightly, producing that characteristic squeal.
This is especially noticeable when:
- The charger is under a light load (for example, charging a nearly full phone).
- You’re using the charger in a silent environment.
- The components are slightly loose or not well-damped.
👉 Low-quality or aging components
Cheaper chargers often use lower-quality capacitors and coils, which may vibrate more easily. Over time, as parts degrade or glue inside the charger dries out, vibration and resonance can worsen, leading to a louder or more persistent whine.
👉 Voltage fluctuations
If your home’s electrical supply is unstable, small voltage surges or dips can affect how your charger’s internal circuitry operates, potentially creating noise as it adjusts to maintain stable output power.
👉 Charging behavior and load
You may notice the sound changes depending on whether a device is plugged in or how full its battery is. This is because power draw fluctuates, and the charger adjusts its switching frequency accordingly. At lower loads, the switching frequency may drop into the audible range, making the noise noticeable.
👉 Environmental factors
Temperature and humidity can influence how electronic components behave. In colder conditions, materials contract, sometimes tightening or loosening internal parts in ways that make vibrations more audible.
When is it normal?
In most cases, the noise is completely normal and not a sign of danger. Here are a few situations where it’s nothing to worry about:
👍The charger only makes noise when idle or charging slowly
Some chargers emit a faint squeal when your phone’s battery is nearly full and drawing minimal power.
👍 You only hear it in very quiet environments
If the sound is faint and disappears when charging is active or when you move farther away, it’s usually harmless.
👍 It’s a reputable brand charger
Original or certified chargers from well-known brands are built with safety standards in mind, so a bit of noise doesn’t mean it’s unsafe.
Phone charger making high-pitched noise: Warning signs
Some sound is harmless. But there are certain cases in which a high-pitched noise may signal a serious issue. Watch out for these warning signs:
⚠️ The charger gets very hot or there’s a burning smell
Excessive heat or a burning smell is never normal. It could indicate a short circuit, component failure, or poor insulation. These things can lead to electric shock or fire hazards.
⚠️ The noise is sudden or very loud
If the charger suddenly begins making a much louder or sharper sound than usual, especially after months of silent operation, it might suggest an internal failure like a failing capacitor or transformer.
⚠️ Intermittent power or flickering charge
If your phone’s charging indicator keeps turning on and off, or charging is unusually slow, the charger could be malfunctioning internally. The noise may be a symptom of unstable power output.
⚠️ Physical damage
A cracked casing, frayed cable, or exposed metal parts are serious red flags. Combined with noise, these signs warrant immediate discontinuation of use.
⚠️ It’s a counterfeit or unbranded charger
Fake chargers – especially those imitating Apple, Samsung, or other premium brands – often cut corners on insulation, grounding, and component quality. They might whine loudly and also pose real electrical hazards.
Safety tips
Let’s end with some safety tips for phone chargers. Even a good charger can fail if misused. Here are some tips to maximize safety and longevity:
✅ Unplug chargers when not in use – this reduces wear and eliminates unnecessary power draw.
✅ Avoid covering chargers with blankets or clothes – chargers need ventilation; covering them can trap heat and shorten their lifespan.
✅ Use surge protectors – sudden voltage spikes can damage your charger and cause it to whine or fail prematurely.
✅ Stick to original or certified accessories – counterfeit chargers might be cheaper but often lack proper insulation and overload protection.
✅ Keep chargers away from moisture – water and electronics don’t mix; humidity can cause arcing or corrosion.
✅ Replace old chargers periodically – like all electronics, chargers wear out over time. If yours is over 3-4 years old and starting to make noises, consider upgrading.
