Using CD4013 to implement dual-function button circuit

Usually, when we require an operating button to realize two functions in an application, we mostly have to rely on a single-chip microcomputer to complete it. In the absence of a single-chip microcomputer, we have to use two buttons separately, or adopt double-pole switching and other methods.

Here we introduce a circuit composed of triggers, which can realize the dual functions of power on/off by operating the key for a certain period of time, and can be used in many small game machine circuits. The circuit is shown in the figure below.

In the figure, the incandescent lamp HL replaces the electrical equipment. When SB is pressed, R1, C1 and R3, C2 form two integration circuits. According to the characteristics of the CD4000 series, when the potential of the CLK (pin 3 of CD4013) and R (pin 4 of CD4013) ends rises to 1/2∞, the output end of CD4013 changes, and the time when the CLK end arrives is t1 after SB is pressed, and the time when the R end arrives is t2 after SB is pressed. From the above figure, we have:

　　t1=R1C1In2=1(s)

　　t2=R3C2In2=2.29(s)　

That is: when SB is pressed for time t1<t<t2, after CD4013 receives the signal sent by SB at the CLK and D terminals, it makes its 2nd pin low level to turn on VT; when SB is pressed for time t2<t, VT is turned off.