220V to 9V AC and 18V-0-18V AC 2A Dual Output Center-Tapped Step-Down Transformer

Product Overview

This 2A step-down power transformer converts a 220V AC mains input into two separate low-voltage AC outputs. The secondary side provides one 0-9V AC output through two wires and one center-tapped 18V-0-18V AC output through three wires, giving a total of five secondary output wires.

The separate secondary windings make this transformer suitable for projects that require a dedicated 9V AC supply together with a higher-voltage symmetrical 18V-0-18V AC supply. After adding suitable rectifier, filtering, and voltage-regulation circuits, the outputs can be used to build single-rail or positive and negative DC power supplies for amplifiers, control systems, and other electronic circuits.

Key Features

• Designed for a 220V AC primary input through two input wires.
• Two independent low-voltage AC secondary outputs.
• Separate 0-9V AC winding with two output wires.
• Center-tapped 18V-0-18V AC winding with three output wires.
• 2A transformer current rating as specified.
• Suitable for higher-voltage dual-rail power supply applications.
• Laminated iron-core construction for conventional mains-frequency power conversion.
• Open-frame chassis-mount design with metal fixing brackets.
• Provides electrical isolation between the primary and secondary windings.
• Suitable for amplifiers, power supplies, chargers, control circuits, and DIY electronics.

Output Configuration

Technical Specifications

Understanding the 18V-0-18V Output

• Each outer 18V wire measures approximately 18V AC relative to the center-tap wire marked 0V.
• The voltage measured between the two outer wires is approximately 36V AC.
• The center tap can be used to build symmetrical positive and negative DC power supplies after suitable rectification and filtering.
• The separate 9V AC winding can power another compatible circuit within the same project.

Applications

• Dual-polarity regulated power supplies.
• Audio power amplifiers and preamplifier circuits.
• Analog and operational-amplifier projects.
• Industrial control and instrumentation circuits.
• Battery charger circuits with suitable rectification and regulation.
• Microcontroller and embedded-system power supplies.
• DIY electronics and educational projects.
• Circuits requiring both 9V AC and 18V-0-18V AC supplies.

Package Contents

• 1 x 220V to 9V AC and 18V-0-18V AC 2A Step-Down Transformer

Important Notes

• All listed secondary voltages are AC outputs, not DC outputs.
• A bridge rectifier, smoothing capacitors, and suitable voltage-regulation components are required when a DC output is needed.
• The DC voltage after rectification will be higher than the stated AC voltage when unloaded, so all components must be selected with suitable voltage ratings.
• The 220V primary side is hazardous and must be installed only by a qualified person.
• Use a suitable fuse, insulated enclosure, proper earthing where required, and adequate spacing between the mains and low-voltage sides.
• Never identify the wires only by color. Confirm every winding and voltage using the transformer marking, continuity testing, and a suitable multimeter before connecting a load.
• Do not connect the separate secondary windings together unless their winding arrangement and phase relationship have been correctly verified.
• Do not exceed the rated current, as excessive loading may cause overheating and permanent transformer damage.