8. Trace a transistor
Rodriguez can make current/voltage plots of NPN and PNP transistors. Keep in mind that it can only reach 5V and about 5 milliamperes of collector current.
Transistor measurements are made using both driven outputs (filtered D9 and D10.)
The filtered D9 output goes to the base of the transistor. The filtered D10 output goes to the collector.
The emitter of NPN transistors must be connected to ground. The emitter of PNP transistors must be connected to the 5V supply of the Arduino.
- If you are using a solderless breadboard, refer to Breadboard setup NPN or Breadboard setup PNP.
- Connect the filtered output of D9 to the base of the transistor. For most transistors you will need to use an additional resistor in series with the D9 output. That is in addition to the standard 3.3k base resistor shown in the Rodriguez schematic. Do not add the value of the additional resistor to the R_base value in the Rodriguez settings.
- Connect the filtered output of D10 to the collector of the transistor.
- Connect the emitter of the transistor to ground if it is an NPN transistor. Connect the emitter of the transistor to 5V if it is a PNP transistor.
- Enter the device name in the field "Device name:" - the device's name will appear at the top of the trace area.
- Select the number of traces to make. Keep in mind that Rodriguez is slow. Make as many as you need, but no more.
- Select the transistor type. Make sure your transistor is of the correct type and that you have connected it correctly.
- Hit "Run" and wait for Rodriguez to do its thing. You may want to take a coffee break or a short walk around the block. Rodriguez is slow.
