Electrical – Circuit with a single buzzer but multiple L.E.D and switches


I need to design a circuit that has three LEDs, each LED has its own push button switch, but there is only one common buzzer.

Goal: when a push button is pressed its corresponding LED should glow along with the buzzer sound.

  1. Design the circuit with single battery source.
  2. Design the circuit with two battery sources such that when a push button is pressed LED should glow from one battery source and buzzer should sound from other battery source.

Please help me with either of the above two circuit diagrams.

Best Answer

This is simply 3V batteries with LED and Current limiting switch with Diode OR logic. and a 3V Piezo Buzzer .


simulate this circuit – Schematic created using CircuitLab

  • If White LEDs then no 50R resistor needed, if 3V battery max. If Red or Yellow 2~2.1V , 0.9V drop/50~18mA
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