Which diagram is correct for the ladder diagram where TR is an ON-Delay relay?

In ladder logic, an ON-delay relay is used to create a delay in the circuit, meaning that once the relay's coil is energized, there is a brief period before the relay contacts close. This allows for time-based control in various applications.

The ladder diagram depicting the ON-delay relay should clearly show the relay coil connected to the start circuit and the relay's contacts in a series or parallel configuration as required by the logic of the circuit. In the correct diagram, the relay coil would likely be positioned in such a way that when it is energized, it eventually closes its associated contacts after the specified delay period.

Certain key characteristics are typical for an ON-delay relay: once the input conditions to the relay are met, it begins the timing sequence. The appropriate diagram would reflect this sequence, showing that the output control only activates after the relay has finished its delay timing.

In context, the other diagrams may illustrate different configurations or depict relays that function differently, such as OFF-delay relays, or may not correctly indicate the timing and operation principles of the ON-delay relay. The correct illustration captures the essence of how an ON-delay relay operates within a control circuit, helping students understand how these elements interact in practical electrical systems.