Choosing a 12V DIN rail power supply for your industrial power supplies transformers setup is more involved than just picking a box. You have to match voltage and current to your control circuit, decide whether you need status signals, and think about where the supply will live. The MEAN WELL MDR-100-12 and the NDR-120-12 are two 12V DIN rail converters that take different approaches to that problem. One is priced lower and packs in monitoring features; the other costs more and offers a higher output rating. The price gap is modest, but the output and feature differences can change how you wire the panel. Understanding which trade-off matters for your application will make the choice straightforward.
Quick verdict: The MDR-100-12 is the budget-leaning, feature-rich option; the NDR-120-12 is the higher-capacity, more flexible option. If your load is modest and you want an LED and a DC OK signal, the MDR makes sense. If you need more current headroom or want the option of an outdoor-rated enclosure, the NDR is the one to buy. Neither supply is a compromise on basic 12V delivery, but they serve different panel layouts.
Both supplies share the basics you'd expect from a 12V DIN rail power supply: they're new, they mount to a standard DIN rail, and they output 12V DC for control gear. The differences show up in how much current you can draw, where you can install them, and how much status feedback you get.
Here is a compact look at the listed specs that matter most:
| Spec | MDR-100-12 | NDR-120-12 |
|---|---|---|
| Price | $29.99 | $39.99 |
| Output | 7.5A, 90W | 10A, 120W |
Where each wins: The listed price spread favors the MDR-100-12, which comes in as the lower-priced of the two while still giving you adjustable voltage, an LED indicator, and a DC OK signal. The NDR-120-12 counters with a larger current window and a higher power rating, plus broader installation flexibility. So the decision hinges on whether you value feedback and savings or capacity and siting freedom.
MDR-100-12
The MDR-100-12 is the white, enclosed MEAN WELL supply for indoor DIN rail panels. It includes adjustable voltage, an LED indicator, and a DC OK signal, turning a simple AC/DC converter into a monitorable part of your control system. The DC OK signal can be routed to a PLC input or a panel lamp, which is a big step up from a bare converter. At 100mm deep and 90mm tall, it slips into shallow cabinets without crowding adjacent components. The price advantage is clear: it's the lower-priced unit of the two. The trade-off is that it's positioned for lighter loads, so if your circuit frequently approaches the top of its rating, you'll be running near the edge.
NDR-120-12
The NDR-120-12 is the blue, DIN rail-mounted supply that brings an indoor/outdoor rating to the table. That rating is the standout reason to choose it when the power supply isn't fully sheltered, since it gives you more enclosure choices from the start. The blue housing also helps you tell it apart from the rest of the rail at a glance, which is handy in a dense cabinet. The main limitation is price: it's the more expensive of the pair, so you'll want to confirm that the broader placement flexibility and higher output justify the extra cost. If your load is genuinely heavy, the larger current window gives you real headroom on a 12V bus.
Final choice by use case: For a straightforward indoor control cabinet with a modest current draw, the MDR-100-12 at $29.99 is the sensible pick. For a circuit that needs a higher output rating or an installation that might be exposed, the NDR-120-12 at $39.99 is worth the higher price.
