4/13-4/17: Light Bulb!

The most profound thing I learned last week had to be in regards to a circuit board we used that simulated the running lights on a truck. Everything worked as it was supposed to on the board, however, we were asked an interesting question. Why did the turn signal light alternate on/off opposite as the brake/turn signal light when the turn signal was activated?

As you can see, power goes to both bulbs when the lights are activated. However, when the turn signal is activated through the board, a relay is activated and sends power down through the right hand side of the circuit which leads to the RH Front park/turn light and sends positive flow to the other side of RH right marker light and thus taking away its closed circuit. When the relay disconnects the current flows back through RH right marker light and has a complete circuit by making RH front park/turn light essentially a ground.