Day 3/4, Lab 2

Lab was split into three parts.

Part 1: Build one circuit on paper using copper tape. Your circuit should have at least one LED and some kind of switch. Get creative with how the circuit turns on and off.

Part 2: Build a custom switch (out of fabric, copper tape, paper, etc..) that connects to your breadboard and turns on an LED. Replace the switch from your circuit in Lab 1 with this custom switch.

I just added on to Lab 1 here, see captions

Breadboard and enclosure from Lab 1 used, copper tape hooked around and on top for a button


can either press on the button, or press down on the chimney
little tape “holder” used to keep the button in place so you can keep the LED on.

Part 3: On a breadboard, build two circuits, each with a minimum of two LEDs. One circuit should have the LEDs in series and the other should be in parallel. Use Ohm’s Law to calculate the necessary resistor values in these two circuits given your particular power source. Draw schematic diagrams of each breadboarded circuit.

Series circuit


Parallel circuit



Voltage = 5V after the voltage regulator switches the 9V to 5V

Each Red LED is roughly 1.8 V drop across and the current through each is 0.02A


I = 0.02A

R = V / I = (5 – 1.8-1.8) / 0.02 = 70 Ohm


Itotal = 0.02 + 0.02 = 0.04A for each red LED

R = V / I = (5 -1.8) / .04 = 80 Ohm

Series circuits have a constant current through each component, but the voltage drops over each one so you need to make sure you have enough voltage overall.

Parallel circuits split the current but over each one the voltage is the same. So ultimately, running LEDs in parallel will supply the same limited amount of voltage to each LED which you could string up more than what the voltage “allows” because the current is split instead of the voltage. Basically each LED will be supplied with the full 5V from the power supply.



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