I am trying to build a more complex circuit but am having trouble starting off. I am using tone() to generate a frequency on my 5V Arduino Nano on D3. If I measure the frequency directly at D3 to GND, I measure a consistent 123.15hz which is what I'm looking for. Now, If I use an NPN transistor(I have tried a S8050 and BC337) the frequency jumps between 107hz and 123hz when I measure at the emitter. I am using a 1k ohm resistor in between D3 and the base of the NPN.
Any suggestions would be greatly appreciated.
Thank you.
Best Answer
1st، as others have pointed out this problem, you have to change your wiring, connect the +5v wire to the collector (left side pin of the transistor in the schematic) & connect GND wire to the emitter (right side pin of the transistor)
2nd, in this schematic, you are measuring the current of transistor's output, not it's voltage. Remove the measuring instrument, replace it by a resistor as your load, then connect the measuring instrument to the load resistor in parallel (connect measuring instrument to both pins of the load resistor).