A 50 Hz power-frequency transformer (iron core + copper windings). It only performs voltage step-down (e.g., 220V → 12V/24V). The output is analog and unregulated, representing a passive power supply.

Essentially equivalent to a switched-mode power supply (SMPS): AC is rectified → high-frequency switching → high-frequency transformation → rectification. Controlled by PWM controllers or microcontrollers (MCU). It integrates power regulation, protection, and control, forming an intelligent power supply system.

Operates at 50 Hz, requiring a large magnetic core, resulting in bulky size and heavy weight.

Operates at high frequencies (tens of kHz or higher), significantly reducing core size. It is lighter, more compact, and suitable for embedded designs in compact door operators.

Lower efficiency, especially under light-load conditions. Continuous core (iron) losses exist even at no load, leading to noticeable heat generation.

High efficiency (typically 80%–95%), lower heat generation, and low standby power consumption. More suitable for long-term standby operation in door systems.

Output voltage varies with input fluctuations. Voltage drops under heavy load, potentially causing control board malfunction or unstable motor torque.

Provides regulated output (e.g., stable 24V). Maintains stable voltage under grid fluctuations and load changes, ensuring smooth and reliable door operation.

Minimal protection (typically only a fuse). Short circuits may lead to permanent damage.

Typically integrates multiple protections: over-voltage, over-current, hort-circuit, over-temperature, and soft-start. Significantly improves safety and durability.

Output is uncontrollable. Speed regulation requires additional circuitry. Startup and stopping shocks are significant.

Compatible with PWM-based motor control. Supports soft-start and soft-stop, enabling smoother operation and reduced mechanical stress, thereby extending service life.

Low external electromagnetic interference (advantage), but limited overall system-level immunity.

When properly designed, offers strong EMI immunity with filtering and suppression techniques. Poor designs may introduce high-frequency noise, though this is generally not an issue in compliant products.

Simple structure, highly robust, and long service life (often >10 years). Resistant to surge conditions.

More complex (ICs, capacitors, etc.), sensitive to environmental conditions (temperature, humidity). Lower-quality designs may have reduced reliability.