12-0-12V 1A Center-Tapped Step-Down AC Transformer

12-0-12V 1A Center-Tapped Step-Down AC Transformer is a heavy-duty EI laminated silicon-steel core step-down mains transformer engineered to step down 220V–240V AC (50Hz) household utility power to a galvanically isolated 12V–0–12V AC Center-Tapped (12V AC or 24V AC end-to-end) output rated at 1.0 A (1000 mA). Wound with high-purity enameled copper magnet wire on a flame-retardant split bobbin with steel chassis mounting brackets, this transformer provides low-noise, magnetically isolated AC power ideal for linear DC power supplies, full-wave bridge rectifiers, audio amplifiers, and microcontroller transformer power stages.

Key Features:

• Galvanic Mains Isolation: Complete magnetic isolation between the 230V AC primary winding and low-voltage secondary winding protects users and low-voltage circuits.
• High-Permeability EI Laminated Core: Low-loss silicon-steel laminations minimize eddy current losses, mechanical hum, and no-load heating.
• 12V–0–12V AC Center-Tapped (12V AC or 24V AC end-to-end) Output: Delivers 1.0 A (1000 mA) continuous AC current (24 VA apparent power rating).
• Color-Coded Flying Wire Leads: Pre-stripped flexible PVC-insulated primary and secondary wire leads allow quick soldering or terminal block connection.
• Rigid Steel Mounting Clamp: U-channel metal frame with dual mounting ears secures directly to enclosures or wooden project boards.

Technical Specifications:

• Transformer Type: EI Core Step-Down Mains Isolation Transformer
• Primary Input Voltage: 220V to 240V AC, 50Hz / 60Hz
• Secondary Output Voltage: 12V–0–12V AC Center-Tapped (12V AC or 24V AC end-to-end)
• Rated Secondary Current: 1.0 A (1000 mA)
• Apparent Power Rating: 24 VA
• Winding Material: Enamel-coated copper / high-grade magnet wire
• Insulation Class: Class B (130°C) dielectric bobbin insulation

Mechanical Specifications:

• Core Construction: Stacked EI silicon-steel laminations with varnish impregnation
• Mounting Style: Horizontal chassis mount with 2 × slotted mounting tabs
• Primary Terminations: 2 × Insulated Red/Black AC input wire leads
• Secondary Terminations: 3 Secondary Wires (12V – 0V Center Tap – 12V)
• Weight: Approximately 420 g

Dimensions:

• Core Length (with Mounting Tabs): 68.0 mm
• Core Width: 56.0 mm
• Core Height: 56.0 mm

Pinout and Wiring:

• Primary Winding (2 Wires — Typically Red/Red or Black/Black): Connect to 220V–240V AC 50Hz Mains (Always insulate primary connections and include a 0.5A/1A primary fuse).
• Secondary Winding (3 Secondary Wires (12V – 0V Center Tap – 12V)): Connect to an AC load or a 1N4007 / W10M diode bridge rectifier and smoothing capacitor to produce DC voltage.

Datasheet Reference:

• Refer to standard EI-Core 230V 50Hz Linear Power Supply Transformer design guidelines and LM78xx / LM317 rectifier application notes.

Commonly Used in:

• Linear regulated DC power supplies using 7805, 7809, 7812, LM317, or LM337 voltage regulators
• Dual-rail (±12V / ±9V / ±5V) op-amp and Class-AB audio amplifier power supplies
• 12V/6V battery trickle chargers and relay control boards (such as XH-M601)
• College electronics engineering lab rectifiers, inverters, and power electronics projects

Applications:

• Full-Wave & Bridge Rectification: Converting 230V AC mains to smooth low-voltage DC with a diode bridge and electrolytic filter capacitor.
• Low-Noise Analog Power: Supplying ripple-free linear power to sensitive audio preamplifiers and analog instrumentation without high-frequency SMPS switching noise.
• AC Reference Signal Generation: Providing isolated 50Hz AC waveform references for zero-crossing detectors and smart energy meters.

Equivalent Models:

• HLK-PM01 / HLK-PM12 PCB AC-DC Module: Ultra-compact encapsulated switching power supply module for space-constrained PCBs.
• 12V 2A / 5A Metal SMPS: Regulated switching DC power supply for higher current demands.

Package Includes:

• 1 × 12-0-12V 1A Center-Tapped Step-Down AC Transformer