Dual Turn On Timer Using the 4093 IC (ART182E)

The circuit can be used as a sequential timer in several types of automatic systems. For instance, you can use this circuit as part of an “intelligent” alarm, first turning on a siren and then, after some minutes, a lamp. The second action of the circuit, turning on the lamp, suggests to the intruder the presence of another human in the vicinity.

You can use it to replace a more complex resource such as the Arduino for simple purposes.

The circuit can be powered from 6 or 12 V supplies. In alarm systems, you should use heavy-duty batteries or ac power supplies, because, when closed, the two relays drain an amount of current exceeds the capacity of small AA cells and other small batteries.

With the dual time delays, you can obtain a total time delay of up to an hour and half.

A schematic diagram of the Dual Turn-On Timer is shown in Fig.1.

Figure 1 – Schematic diagram of the Dual Timer

Proper positioning of the polarized components (the two diodes and the electrolytic capacitors) must be observed. Using mini DPDT relays, it’s easy to build a compact unit, as these components can be mounted directly on the solderless board or universal printed circuit board.