Can anybody explain how the inverter circuit works?

Question

If transistor is just like a switch, it shouldn't affect the led since it forms a closed loop with the battery. So why does the led turn on and off?

I am new to digital electronics(and electronics in general) any help is appreciated.

Thanks in advance.

Answer 1

^{simulate this circuit – Schematic created using CircuitLab}

Figure 1. The equivalent circuit using a relay.

• When the relay coil is un-powered the LED is lit.
• When the relay coil is powered the contact closes and short circuits the LED. It turns off.

Note that the circuit is a little inefficient. Not only does it draw power when the LED is off but it draws more power in that condition as the full voltage is across R1.