Circuit Project Electronic

With this circuit you can can check that which dot of the circuit is Positive Volt or Negative Volt which. This cheap circuit uses the a little component is will appropriate apply with an automobile or motorcycle. This circuit works during Voltage between 5-15V. When build volt supply of circuit LED 2 pcs. of stick bright but enough check meet Positive Volt make at pin 3 of IC 555 liberate Negative volt come out cause Red LED stick bright next but Green LED switch off down replace. But when check meet Negative Volt make Red LED switch off but Green LED stick bright replace yes . The Diode 1N4002 be formed protect turning pole electricity over. The detail is other , see in the circuit please sir.