What differentiates this circuit from the previous one (CB12689E) is the non-need to use a symmetrical source. This allows the supply to be even made with a lower voltage. In the figure we have the configuration that also activates an LED indicator. To obtain the reference voltage equal to half the supply voltage, a divider with resistors R2 and R3 is used. The values of these resistors are not critical and as long as they are the same, they can typically be in the range of 10k to 47k ohms. In this case too, it is possible to use an excitation step with a transistor to control higher power loads, such as a relay.
