EI28 Low Frequency Power Transformer 220V to 12V –Vertical PCB Pin Mount Core Voltage Converter
It is mainly used to reduce the high input voltage to the appropriate voltage required by the device. During the voltage reduction process, the principle of electromagnetic induction is utilized to achieve voltage conversion through the turns ratio of the primary winding and the secondary winding. Due to its compact structure and stable performance, it is widely used in various electronic devices that require voltage reduction.
Application Specifications
| Parameter | Specification |
| Model | EI28 |
| Product type | Low-frequency step-down power transformer, EI laminated core |
| Mounting | Vertical PCB pin mount (solder-in) |
| Input voltage | 220V AC, 50/60Hz (primary pins 1-2) |
| Output voltage | 12V AC (secondary pins 3-5) |
| Frequency | 50/60Hz |
| Rated capacity | Customized — built to the voltage and current required by the circuit |
| Core | EI28 laminated core; Z11 silicon steel sheet |
| Winding | 100% copper wire |
| Bobbin | Nylon, double-slot vertical |
| Enclosure | Blue steel shell |
| Temperature rise | Under 20°C |
| Product size | 28.5mm |
| Certification | RoHS compliant; ISO 9001:2015 certified manufacturing |
| MOQ | 1000 pieces |
| Lead time | From stock or 3 weeks |
| Supply capacity | 1000K pcs per month |
| Packing | Carton; 15 × 10 × 8 cm, 0.15 kg per piece |
Product Features
● EI28 Laminated Silicon Steel Core: Stacked EI core in Z11 silicon steel sheet for stable magnetic performance.
● 220V to 12V Step-Down Winding: Standard 220V AC primary with a 12V AC secondary (pins 1-2 in, 3-5 out).
● Vertical PCB Pin Mount: Solder-in pins mount the transformer directly on the board and save enclosure space.
● 100% Copper Winding: High-purity copper wire keeps resistance and losses low.
● Nylon Double-Slot Bobbin: Primary and secondary windings sit in separate slots of a nylon bobbin.
● Blue Steel Shell: Protects the bobbin and windings against dust, knocks and crushing.
● 50/60Hz Compatible: Runs on both mains frequencies.
● Low Temperature Rise: Under 20°C, supporting long-term continuous operation.
Product Advantages
● Precise step-down ratio: the primary-to-secondary turns ratio is configured to deliver the exact low voltage the downstream circuit needs.
● EI28 core in Z11 silicon steel sheet: the laminated EI structure reduces magnetic leakage, so power transfers efficiently from the primary to the secondary side.
● 100% copper windings: high-purity copper wire minimises resistance and power loss during operation.
● Stable output: inherent voltage-regulation characteristics hold the output steady even when the input voltage or the load changes.
● Low temperature rise, under 20°C: heat from winding and core losses is dissipated efficiently, so the transformer holds its performance under continuous load and lasts longer.
● Compact footprint with vertical PCB pins: a small board area and no external wiring, which suits small devices and tightly packed boards.
● Low electromagnetic interference: optimised winding technique limits EMI, so the transformer can sit next to sensitive components and communication circuits.
● High reliability: high-quality materials and controlled manufacturing let the unit handle normal working conditions plus occasional electrical transients and mechanical vibration.
Application scenario
Application
Power adapters for small appliances
Steps 220V mains down to the low voltage the adapter circuit regulates.
Power supply modules in electronic devices
The board-mounted low-voltage stage ahead of rectification and regulation.
Compact PCB assemblies
Vertical pin mounting fits boards with tight layouts.
Portable equipment and small chargers
Limited internal space, where a small EI28 body is an advantage.
Precision instruments
A stable low-voltage input for measurement and control circuits.
Communication equipment
Low EMI behaviour suits systems that are sensitive to interference.
Product Details Showcase
Quality & Testing Assurance