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Category: Test & measurement
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     I need to detect the source of a short circuit break among some circuits that are in series. This was happened every 2-5 days and all the other time all seems normal. So this circuit is designed. It was applied to every circuit in order to find which circuit is the source of the short break. If a circuit makes even a short circuit break the LED is light and stays so. So I can determine if a small circuit break is happened. The white cable is going to the circuit to be tested. It is powered from 12-13.8 V with a battery to eliminate the false alarm from a power fail. The lead with the fuse is the positive. The relay is a small 12 V one. One 1 Kohm, a LED and a push ON button is also needed. The fuse is any from 315 mA to 2A. When power is applied the LED lights even the circuit is OK. We need to arm it once. We can arm it again if it detects a circuit break and lights the LED. The logic of this circuit is the relay that is closed and stayed closed in series with the circuit under test. A small circuit break open the relay as the coil is in series with its contact.