This is a 555 one shot timer circuit. The circuit will not repeat it's timing cycle if the push switch S1 will remain ON or pressed, after a timing cycle is completed. In the place of the push switch S1 / trigger switch you can also connect the output of any project to trigger the timer.
The heart of the circuit is
a 555 timer IC. A relay switch is connected at the output of the IC from which you can connect any AC or DC appliance to operate it with this one shot timer circuit.
The operating voltage of the relay should be same or near as the operating voltage of the circuit, for example if you are operating the circuit with 6V then use a 5V or 6V relay.
The time duration of the circuit is depends on the capacitor Cx, a 10uF electrolytic capacitor used in the circuit will give the time duration of few seconds, but increasing the value of the capacitor will also increase the duration. For example a 1000uF or 2200uF electrolytic capacitor will increase the time period to hours.