Feature: Switches
Table 1: Three tactile switches across a size range
the unspoken assumption is usually that this will be the same switch in a smaller package: same feel, same life, same behaviour – just occupying less board area. T at assumption is where a good deal of avoidable disappointment begins. A tactile switch is a small mechanism, and there is no way to
A The
engineering of switch miniaturisation
By Liu Junxiong, R&D engineer, Swiclick
shrink the package without redesigning the mechanism inside it. What arrives is not a scaled copy of the original but a diff erent switch built to a diff erent balance of several properties, which neither move together nor in the directions a catalogue may state.
“Size” is fi ve numbers, not one T e fi rst misconception worth abandoning is that size is a single dimension. A tactile switch has at least fi ve properties a designer treats as size, or as the concept of size: • Footprint – the X and Y area it occupies on the board; • Height – the Z dimension above the board, including any actuator or stem;
• Actuation force – required to register a press; • Travel – the distance the actuator moves between rest and the point of actuation;
• Rated life – the number of operations the contact can be trusted to deliver. A data sheet reduces these to a row of fi gures, which invites the
reader to treat them as fi xed and independent. And yet, they are neither. Each is the outcome of the same small mechanism, so a change in one is almost always paid for somewhere else. Let’s illustrate this: Consider three real tactile switches from
across a size range, taken from the Swiclick’s own range (Table 1), labelled as A, B and C. None of the three is a resized version of another. T ey are separate designs, each built around a diff erent priority, and comparing them shows what that costs. All three are signal-level parts rated at 12VDC, 50mA, so
16 September 2026
www.electronicsworld.co.uk
smaller tactile switch is never simply a smaller version of the same switch. Each size is a diff erent mechanism striking a diff erent balance, and the balances rarely fall where intuition suggests. When a design team asks for a smaller switch,
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