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13. Hook-up and use
Connect the unit with a 12VDC regulated power supply as shown in the example.
Turn the trimmer all the way counterclockwise.
Push the START button. The relay will be activated momentarily.
The position of the trimmer determines the ON-time. Turn it clockwise to increase the ON-time.
Increase the value of C2 for an even longer activation duration.
The unit can be stopped at any time by pressing the STOP button.
The START and STOP buttons can be mounted in a remote location. Make sure to use screened cable,
avoid outside interference and keep the distance between the switches and the PCB as short as possible.
The timer is equipped with a relay output that is galvanically separated from the rest of the circuit for extra
safety. The connection example lists the function of the pins of the relay contacts.
If the relay is used to switch important inductive loads, such as electric motors or transformers, it may be
necessary to install a snubber network across the relay contacts to avoid excessive contact wear.
Ensure that the power supply of the circuit is sufficiently HF decoupled. Noise impulses entring
trough the power supply may start and stop the circuit unnecessarily.
Hook-up and use
9
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