What Are Power Supplies?
Power supply components convert, regulate, and distribute electrical power to electronic systems. The category includes AC-DC converters (wall adapters, open-frame supplies), DC-DC converter modules, power over Ethernet (PoE) modules, voltage reference ICs, and power inductors and transformers used in switching power supplies. LCSC Electronics stocks 20,000+ power supply SKUs from 200+ manufacturers, covering solutions from milliwatt IoT power to multi-hundred-watt industrial supplies.
Power Supplies — Definition and Sub-Categories
A power supply converts electrical energy from one form to another — typically from AC mains to regulated DC, or from one DC voltage to another. Power supplies are classified by input source (AC or DC), output regulation method (linear or switching), isolation (isolated or non-isolated), and form factor (module, open-frame, enclosed, on-board).
|
Sub-Category |
Function |
Key Parameters |
|
AC-DC Converters |
Convert mains AC to regulated DC |
Input range, output voltage/current, efficiency, isolation |
|
DC-DC Modules |
Board-mount voltage conversion modules |
Vin/Vout, current, isolation, size |
|
PoE Modules |
Power extraction from Ethernet cables |
IEEE standard (802.3af/at/bt), power class, output voltage |
|
LED Drivers |
Constant-current supplies for LED lighting |
Output current, dimming method, power rating |
|
Voltage References |
Precision voltage sources for ADCs and DACs |
Accuracy, drift (ppm/°C), output voltage, noise |
How to Choose: Power Supplies Selection Guide
Start with your load requirements: output voltage, maximum current, and acceptable ripple/noise. For AC-DC, verify input voltage range (115V/230V or universal), safety certifications (UL, CE), and isolation requirements. For DC-DC modules, key parameters are efficiency, input voltage range, and thermal performance. For noise-sensitive analog circuits, choose low-noise linear regulators or well-filtered switching supplies. For PoE applications, match the IEEE standard to your switch infrastructure.
Power Supplies Comparison
|
Supply Type |
Input |
Output |
Efficiency |
Best Application |
|
AC-DC Open Frame |
85–264V AC |
5/12/24V DC |
80–90% |
Industrial equipment, embedded systems |
|
AC-DC Adapter (wall) |
100–240V AC |
5/9/12V DC |
85–92% |
Consumer devices, charging |
|
DC-DC Module (isolated) |
9–36V DC |
5/3.3V DC |
80–90% |
Telecom, distributed power |
|
DC-DC Module (non-iso) |
4.5–28V DC |
1.2–5V DC |
90–97% |
Point-of-load, MCU power |
|
PoE Module (802.3at) |
37–57V PoE |
5/12V DC |
88–93% |
IP cameras, access points |
Why Source Power Supplies from LCSC Electronics
LCSC stocks 20,000+ power supply SKUs from 200+ manufacturers including Mean Well, MORNSUN, CUI, and Asian brands. The catalog covers everything from miniature isolated DC-DC modules to high-power AC-DC open-frame supplies. Combined with LCSC’s power management ICs and passive components, engineers can source complete power solutions from a single vendor.
Frequently Asked Questions
Q: What is the difference between isolated and non-isolated power supplies?
An isolated supply has no direct electrical connection between input and output — a transformer provides galvanic isolation for safety and noise rejection. Non-isolated supplies share a common ground between input and output, which is simpler and more efficient but offers no isolation. Use isolated supplies when connecting to AC mains or when safety regulations require it.
Q: What certifications should I look for in AC-DC power supplies?
For products sold commercially, look for UL (US), CE (Europe), and CCC (China) certifications. Medical devices require IEC 60601 compliance. Industrial equipment typically needs IEC 62368-1. These certifications confirm the supply meets safety standards for insulation, leakage current, and fault conditions.
Q: What is Power over Ethernet (PoE)?
PoE delivers both data and electrical power over standard Ethernet cables (Cat5e/Cat6). IEEE 802.3af provides up to 15.4W, 802.3at (PoE+) provides up to 30W, and 802.3bt (PoE++) provides up to 90W. It eliminates the need for separate power cables to devices like IP cameras, access points, and VoIP phones.
Q: How do I calculate power supply size for my project?
Sum the maximum power consumption of all loads, then add a 20–30% margin. For example, if your circuits draw a maximum of 2A at 5V (10W), choose at least a 12–15W supply. This margin accounts for startup inrush, component derating, and efficiency losses.