555 (timer) circuit capable of controlling loads up to 10 A
Long timers are useful for a variety of applications such as pool filter control, aquarium aeration, greenhouse etc. The device described in this article can be set to a maximum time of 45 hours and has the possibility of being deactivated by external sensors as an important feature. The circuit is capable of controlling loads up to 10 A (1100 W in the 110 V network), and uses low cost components. The timer we describe in this article has several important features as well as sweeping a range of times that makes it useful in a multitude of practical applications. Among the main characteristics of the device, we highlight the following: - Turns on or off an external load at the end of the programmed time; - Auto-off at end of timing; - The timing can be interrupted at any time by the signal sent by external sensors; - Covers a range of 3 minutes to 45 hours; - Operates on both the 110 V and 220 V mains, depending only on the choice of the transformer. Since the circuit h...