What is a power supply?
A power supply for an electrical device that converts AC mains voltage to DC voltage used to power a receiver with specific electrical parameters such as voltage, current and power.
What does a power supply do?
A power supply provides the correct power supply parameters for the receiver by converting the mains voltage to DC voltage. This means that the power supply costs the mains voltage and also maintains this voltage at an appropriate level, usually lowering it in relation to the mains voltage, but not only that, and ensures stabilization of parameters such as voltage or current, protecting the receiver against image burnout, ensuring its correct operation. Additionally, depending on the type, the power supply filters the voltage, maintaining its constant level regardless of the load in the case of constant voltage power supplies. Or maintains a set current in the case of constant current power supplies. In the case of constant power supplies, the power supply maintains a specific voltage and current so that the total power output from the power supply does not change.
How does a power supply work?
A power supply works by converting electrical energy from one source into a form suitable for a specific device. This process can involve several stages, depending on the type of power supply. A power supply primarily converts voltage from to the voltage of the receiver and then rectifies it.
Depending on the type:
Linear power supply - equipped with a transformer, structurally simpler power supplies change the voltage through a transformer and then rectify it using capacitors and a voltage regulator.
Switched-mode power supply (SMPS) - through very fast switching using complex electronics, they generate constant voltage and regulate voltage and current parameters
What are the types of power supplies?
Power supplies are divided into:
Constant voltage
- maintain a given output voltage, e.g. a 12V power supply or a 24V power supply used for most receivers such as LED strips, LED modules, electronics such as a router or laptop
Constant current
- maintain a given output current - used where there is a need to overheat and burn out the receiver, e.g. a POWER diode LED.
Constant power
-provide constant output power regardless of voltage and current changes. In practice, this means that the power supply automatically adjusts its output voltage and current so that the product of these two values (i.e. power) remains at a constant level.
How to connect the power supply?
The power supply is connected with wires marked in brown and blue to the mains voltage, and to the receiver with red and black wires. It is important to always follow this rule. Additionally, the red wire informs us about the positive voltage, i.e. +
What power supply for LED strips?
LED strips require a constant voltage power supply, e.g. 12V or 24V. You can recognize the type of strip by the number of diodes between the places intended for cutting. LED strip cut every 3 diodes requires a 12V power supply, while LED strip cut every 6 or 7 diodes requires a 24V power supply. You should also remember about the appropriate power supply capacity, which should be about 20% - 25% higher than the power of the strip. We can calculate the power of the strip by multiplying the power of the strip per meter by the number of meters. In the case of strips cut into short sections, the actual power drawn may be higher than declared by the manufacturer.
Why does the power supply squeak?
The humming or squeaking of the power supply usually occurs in the case of cheap power supplies connected to a dimmer. This is because the frequencies of the power supply and the dimmer, when they overlap, cause resonance at the frequency causing the sound. The solution to the problem is to use a higher quality power supply or replace the dimmer with one operating at a different frequency. Some dimmers have a switching frequency to prevent this effect.
Why does the power supply heat up?
A power supply heating up indicates its high load, poor ventilation and high ambient temperature. Although power supplies usually have a power reserve, overcurrent protection only works after exceeding the nominal power. Power supplies usually have a reserve of 110% to even 150% of the nominal power, which means that they will only turn off then. Therefore, if the power supply is mounted in a warm place without ventilation, it is worth choosing a model with a larger power reserve. The reason for overheating may also be a dirty or non-working fan.
How to check the power supply?
First, it is worth inspecting the power supply visually to see if it is not mechanically damaged and for overheated components. Then, you should connect the power supply to the load, simulating a full load and simultaneously measuring
Power supply or transformer?
The difference between a power supply and a transformer is mainly in the type of output current and functions:
Transformer - converts voltage from one level to another, but does not change the type of current. It works on the principle of electromagnetic induction and is mainly used to change the voltage of alternating current (AC) to other voltage levels of alternating current. Transformers do not have most of the additional functions such as power supplies. They may sometimes have thermal protection.
Power supply - In addition to changing voltage, it also converts alternating current (AC) to direct current (DC). Additionally, they have many functions such as voltage stabilization or overcurrent and short-circuit thermal protection
Power supply or charger?
a charger is a more advanced type of power supply. This is due to the characteristics of the battery charging current. In the case of good chargers, we usually have 2 or 3 battery charging phases. This means 2 to 4 different settings of the output parameters in the context of its voltage and current.
What are the battery charging phases?
Pre-charge phase - the charger supplies a low current to gently charge a battery that is deeply discharged.
Bulk charge - the charger delivers maximum current to quickly charge the battery to about 80% of its capacity.
Absorption charge - the charging current is gradually reduced to maintain a constant voltage, still charge the battery but not damage it with too high a voltage.
Float charge - the voltage is lower, this phase is only used to keep the battery fully charged without the risk of overcharging