Light Indicators

This article is about simple light indicators with diode over-voltage protection.

LEDs Indicator

This is the LEDs indicator circuit that I made:

Figure 1: LEDs Indicator.

You can see that I used old food packing as protection in case the components explode due to over-voltage.

Step 1: Design the LEDs Indicator Circuit

I have drawn the circuit in Easy EDA software:

Figure 2: LEDs Indicator Circuit.

Maximum power for R1 resistor:

PmaxR1 = ((Vin - Vd2d3d5d5 - Vd1)^2) / R1
= ((Vin - 2.8 V - 0.7 V)^2) / 10 ohms

Step 2: Build the LEDs Indicator Circuit

I build this circuit on a piece of packaging material.

Figure 3: LEDs Indicator Circuit Construction.

Step 3: Testing

I connected the circuit to signal generator:

Bulb Indicator

This is the bulb indicator circuit that I made:

Figure 4: Bulb Indicator.

You can see that I used old food packing as protection in case the components explode due to over-voltage.

Step 1: Design the Bulb Circuit

I have drawn the circuit in Easy EDA software:

Figure 5: Bulb Indicator Circuit.

PmaxR1 = ((Vin - Vd1d2)^2) / R1
= ((Vin - 1.4 V)^2) / 10 ohms

Step 2: Build the Bulb Circuit

I build this circuit on a piece of cardboard.

Figure 6: Bulb Indicator Circuit Construction.

Step 3: Testing

I connected the circuit to an adjustable power supply:

Conclusion

It is hard to predict the maximum voltage that the component can withstand. Of course, you can do power rating calculations but the components might need cooling systems to work at maximum power rating.