Breakover

Breakover is a term used in several engineering contexts to describe a threshold at which a system changes state or behavior. It most commonly appears in discussions of vehicle geometry and in solid-state electronics, though other fields also use the concept in related ways.

In automotive and off-road design, breakover refers to the breakover or breakover angle—the maximum obstacle angle a vehicle can crest without its underbody contacting the obstacle. The breakover angle is typically estimated from simple geometry using the vehicle’s ground clearance and wheelbase. A common approximate formula is arctan(2G/L), where G is the minimum underbody clearance and L is the wheelbase. In practice, the actual capability depends on variables such as the height and shape of the obstacle, the vehicle’s center of gravity, suspension articulation, tire deflection, and approach and departure angles. Breakover is a key factor in evaluating off-road performance and is often quoted in vehicle specifications alongside ramp and departure angles.

In electronics, breakover refers to the breakover voltage (VBO) of certain semiconductor devices, notably thyristors and related components. Breakover voltage is the forward voltage at which the device switches from a nonconductive to a conducting state in the absence of a trigger signal, typically due to internal regenerative feedback. Once the device breaks over and conducts, it latches on until the current falls below a holding level. Breakover voltage is temperature-dependent and is specified in datasheets; controlling operating conditions and using proper gating or snubbers is essential to prevent unintended switching.

Overall, breakover describes a threshold that marks a transition from one regime to another, with specific meanings varying by field.