Read all the "RC Circuits Transient Analysis with Raspberry Pi and Scoppy" series:

In this second episode we will actually build the circuit and start experimenting.

Prerequisites

Bill of Materials

  • Raspberry Pi Pico board, preferrably pre-soldered (and with PIN stickers applied)
  • Micro-USB cable: used to power the Pico, can be used to connect tablet and Pico
  • a breadboard
  • 3 jumper cables
  • 1 \(10 \mu F\) capacitor
  • 1 \(220 \Omega\) resistor
  • an Android tablet or phone

Optional materials:

  • (opt.) a multimeter
  • more capacitors and resistors

RC Circuit

Set-up

Before doing anything on the breadboard, you should set-up the Raspberry Pi Pico board and Scoppy. On the Scoppy website there's a very detailed tutorial:

https://oscilloscope.fhdm.xyz/wiki/Installation-&-Getting-Started

The steps required are:

  • download and flash the "Erase flash" firmware: ⚠️ BEWARE ⚠️ it will erase all the memory of the Pico!
  • download and flash the correct firmware for your Pico Board (Pico, Pico W, etc.)
  • install the App on your phone or tablet
  • connect the App via USB or Wi-Fi

Once done you can move on to the next step.

Building the circuit

Here is the schematic of out RC Circuit:

RC Circuit

Some important notes:

  • if the capacitor is electrolytic, pay attention to the ⚠️ correct polarization ⚠️: the long leg must be connected to the "+" and the short leg to the "-". Usually, there's a clearly visible white band with minus signs "-" printed all over, to indicate the correct way
  • the red jumper is connected on the 22 Pin, which provides the pulse wave voltage
  • the blue jumper is connected to the 26 Pin, which is on of the ADC inputs of the Pico and corresponds to Channel 1 on Scoppy
  • the black jumper goes to one of the ground (GND) paths on the Pico.

In this picture you can see the complete circuit. I used the same color code as in the schematics, so it should be straightforward to follow:

RC Circuit

Next Steps

In the next article (3 - Measurements and Data Analysis) we will perform some measurements and perform a data analysis.