A light detecting book light.

[Poincare1]

Firstly, the book light works fine. I'm also attaching a circuit diagram.


I don't really understand why the emitter of the transmitter (its marked with an E) takes in the current. Could someone explain to me how this circuit works?

 

[MATLABdude]

Firstly, the book light works fine. I'm also attaching a circuit diagram.


I don't really understand why the emitter of the transmitter (its marked with an E) takes in the current. Could someone explain to me how this circuit works?

There's a circuit diagram?

 

[oswaler]

I would be happy to provide an explanation of how this circuit works. The light detecting book light is a simple circuit that uses a light-dependent resistor (LDR) to detect changes in light and turn on an LED light. The LDR, also known as a photoresistor, is a type of resistor whose resistance changes based on the amount of light it receives.

In this circuit, the LDR is connected to the base of a transistor, which acts as a switch. When the LDR receives light, its resistance decreases, allowing current to flow through it and into the base of the transistor. This turns the transistor on, allowing current to flow from the collector to the emitter, turning on the LED light.

The emitter of the transistor is marked with an "E" because it is the electrode that emits the current from the transistor. In this circuit, the emitter is connected to the negative terminal of the battery, completing the circuit and allowing current to flow.

In summary, the LDR senses changes in light and acts as a switch to turn on the LED light through the use of a transistor. I hope this explanation helps to clarify how the circuit works.