Conditionally short-circuit proof TS bell transformers for supplying extra-low voltage (SELV). Suitable for loads that require a short-term supply, especially doorbells and chimes. In addition to perfect insulation and separation between the primary and secondary circuits, the TS transformers have a thermal protection device integrated in the secondary part, which makes them resistant to short-circuit currents (conditionally short-circuit proof). In addition, the TS8/SW series is equipped with a switch for controlling loads on the secondary output.