A programming mechanism is disclosed for controlling the application of power to apparatus performing successive steps in a process. The mechanism includes an electronic timer for controlling the time period of each step. The timer includes an R-C timing circuit, the R-C constant of which may be adjusted to any suitable value for each different step of the process by connecting into the circuit a different R-C circuit element, such as a variable resistor for each step in the process that the circuit controls. For this purpose, a multisection, multiposition stepping switch is connected to the R-C timing circuit and a different variable resistor is connected to one or more of the terminals of the stepping switch so that as the switch is stepped to the next position a different R-C timing constant may be provided to control the time period of the electronic timer.