120V to 24V 20VA PCB Mount Transformer for Control Boards
Custom-engineered for reliable board-level voltage conversion with copper windings, controlled temperature rise and an application-specific pin layout.
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Custom PCB Transformers Engineered for Your Circuit Board
Compact through-hole PCB transformer with customized input voltage, output windings, rated power, pin layout and insulation construction. ECKO designs each transformer around your load requirements, PCB footprint, temperature-rise target and applicable safety requirements.
From initial electrical calculations to approved drawings, controlled production and routine electrical testing, we help OEM customers integrate reliable mains-frequency power conversion directly into their PCB assemblies.
Typical PCB Transformer Specifications
| Parameter | Typical Range / Available Options |
|---|---|
| Product Type | Open-frame, vacuum-impregnated or fully encapsulated PCB transformer |
| Rated Power | 0.5 VA to 100 VA typical; higher ratings subject to engineering review |
| Primary Voltage | 100V, 110V, 115V, 120V, 200V, 220V, 230V or 240V AC; single or dual primary |
| Secondary Voltage | 3V to 48V AC per winding typical; other voltages available |
| Output Configuration | Single, center-tapped, dual or multiple secondary windings |
| Frequency | 50Hz, 60Hz or 50/60Hz |
| Core Material | EI laminated electrical steel core selected according to power and temperature-rise requirements |
| Winding Material | Copper winding wire |
| Insulation Class | Class B 130°C or Class F 155°C |
| Dielectric Strength | Project-specific; 3.0–4.0kVAC primary-to-secondary options commonly available |
| Temperature Rise | Defined according to rated load, ambient temperature, enclosure and insulation class |
| Mounting Method | Through-hole PCB pins |
| Pin Configuration | Custom pin count, pitch, row spacing, diameter, length and polarity marking |
| Protection Options | Thermal fuse, resettable thermal protector or external PTC coordination |
| Shielding Options | Electrostatic shield, inter-winding shield or magnetic shielding where required |
| Operating Temperature | Typical design range from -20°C to +70°C, depending on the material system |
| Compliance Options | Construction designed for applicable IEC, EN or UL requirements; approval is model-specific |

Specification notice: The values above represent typical engineering capabilities rather than one fixed catalog model. Final electrical ratings, dimensions, tolerances and test limits are defined by the customer-approved specification and dimensional drawing.
PCB Transformer Product Advantages
PCB Transformer Customization Options
| Customization Area | Available Options |
| Electrical Input | Primary voltage, voltage range, 50Hz/60Hz frequency, single primary or dual primary |
| Electrical Output | Single output, dual output, multiple windings, center tap, series/parallel connection |
| Rated Power | VA rating calculated according to each secondary load and operating duty cycle |
| Voltage Regulation | Output voltage adjusted according to the required full-load voltage |
| PCB Footprint | Custom pin position, pitch, row spacing, mounting grid and keep-out area |
| Product Dimensions | Maximum length, width, height, seated height and weight |
| Insulation System | Class B or Class F; functional, basic, supplementary or reinforced insulation |
| Dielectric Strength | Customer-defined or standard-based Hi-Pot level and test duration |
| Thermal Protection | Internal thermal fuse, resettable protector or external protection coordination |
| EMI Control | Electrostatic shield, inter-winding shield and optimized winding arrangement |
| Environmental Protection | Open-frame, vacuum impregnation, tape wrapping or fully encapsulated construction |
| Noise Control | Reduced flux-density design, controlled core assembly and impregnation |
| Identification | Customer part number, polarity mark, date code, batch code and private label |
| Documentation | Product specification, dimensional drawing, pin diagram, test report and material declarations |
| Packaging | Individual trays, partitioned cartons, export cartons and pallet packaging |
Why Choose ECKO for Custom PCB Transformers?
PCB Transformer Tests and Reference Standards
Routine Production Tests
| Test Item | Test Purpose | Typical Inspection Plan |
| Visual Inspection | Workmanship, label, polarity mark, pin condition and product appearance | Routine or sampling |
| Dimensional Inspection | Outline dimensions, seated height, pin pitch and pin position | Sampling or critical dimensions |
| Winding Resistance | Checks conductor continuity and winding consistency | Routine |
| Turns Ratio / Output Voltage | Verifies output voltage and winding polarity at the specified input | 100% routine test |
| No-Load Current | Confirms excitation current, core assembly and winding consistency | 100% or agreed inspection plan |
| No-Load Loss | Evaluates standby core and winding loss | Sampling or qualification |
| Load Voltage and Regulation | Confirms rated-load output voltage and voltage drop | Sample and periodic verification |
| Insulation Resistance | Checks insulation between windings and accessible conductive parts | Routine or sampling |
| Dielectric Strength / Hi-Pot | Verifies the specified insulation withstand level | 100% at the approved test level |
| Temperature Rise | Confirms thermal performance under defined mounting and load conditions | Type or qualification test |
| Audible Noise | Evaluates hum and mechanical vibration at the specified input | When controlled by the specification |
| Solderability | Confirms PCB pin wetting and resistance to soldering heat | Qualification or sampling |
Custom PCB Transformer Development Process
PCB Transformer FAQ
1. Can you match our existing PCB footprint and pin layout?
ECKO can review your PCB hole positions, pin pitch, row spacing, component height and keep-out area. The final footprint must be confirmed through an approved dimensional drawing because pin tolerances and recommended PCB hole diameters can affect assembly.
2. Can the transformer height be reduced to fit a low-profile enclosure?
The height can often be adjusted by selecting a different core, bobbin or winding construction. However, reducing the height may increase the length, width, temperature rise or material cost. Our engineers will evaluate the available PCB area and recommend a practical dimensional arrangement.
3. How is the temperature rise of a PCB transformer determined?
Temperature rise depends on the rated load, input frequency, core flux density, copper current density, ambient temperature, mounting method and enclosure ventilation. It should be verified at rated load under conditions that represent the final equipment as closely as possible.
4. Does potting always reduce the transformer temperature?
Not necessarily. Encapsulation improves mechanical stability and resistance to moisture, dust and vibration, but it also changes how heat is transferred from the windings. The resin system, transformer dimensions and surrounding airflow must be considered during the thermal design.
5. What insulation classes are available for PCB transformers?
Class B 130°C and Class F 155°C insulation systems are commonly available. The selected insulation class does not by itself define the permitted temperature rise; ambient temperature, component ratings, safety standards and the final equipment’s thermal limits must also be considered.
6. Can you design reinforced insulation between the primary and secondary?
Yes, subject to the working voltage, required safety standard, pollution degree, material group, installation altitude and available dimensions. The bobbin construction, insulation barriers, creepage distance, clearance distance and dielectric-strength requirement must be reviewed together.
7. Do you perform 100% Hi-Pot testing on PCB transformers?
Hi-Pot testing can be included as a 100% routine production test. The test voltage, duration, leakage-current limit and test points are defined according to the approved product specification and applicable safety requirements.
8. Can a thermal fuse be built into the PCB transformer?
A one-shot thermal fuse or resettable thermal protector can be incorporated when required. Its operating temperature, current rating, installation position and coordination with the end-product protection system must be confirmed during the design stage.
9. How can audible hum and vibration be reduced?
Audible noise can be reduced through appropriate flux-density selection, accurate core assembly, controlled winding tension and vacuum impregnation or encapsulation. The final equipment enclosure and PCB mounting can also amplify vibration, so any specific noise limit should be stated before sample development.
10. Can ECKO replace an obsolete PCB transformer?
Please provide the original transformer sample, electrical ratings, PCB footprint, pin diagram, application information and any available drawings or test data. A replacement should be verified electrically, mechanically and thermally in the final equipment before mass production.




