How I Wasted a Perfect Saturday With That Stupid 1rfz44n Thing
So last week I found this dusty component box while cleaning the garage. Saw this weird black chip labeled “1RFZ44N” and thought – what the heck is this. Grabbed my phone for a quick search. Oh, some sort of MOSFET thingy. Supposed to handle power switching?
Got curious and decided to mess around with it this Saturday morning. Grabbed:
- My rusty breadboard
- Arduino Uno still crusty from last project
- Random 12V motor from broken toy car
- Trusty multimeter looking sad with missing probes
Slapped everything together like so:
- Arduino 5V pin to MOSFET gate pin
- Motor wires to MOSFET drain/source pins
- Hooked 9V battery to power the motor
Wrote a dirt-simple Arduino sketch:
void setup() { pinMode(9, OUTPUT); }
void loop() { digitalWrite(9, HIGH); delay(2000); digitalWrite(9, LOW); delay(2000); }
Burned the chip twice in 10 minutes. Literally smelled smoke.
Realized I forgot resistors. Of course.
Stuck a 330 Ohm resistor between Arduino pin and MOSFET gate. Less smoke. Progress!
Motor twitched but wouldn’t spin properly. Measured voltage across motor – only 4V when battery’s 9V. What gives?
Scratched head. Remembered MOSFETs need gate voltage higher than source voltage. My dumb setup:
- Arduino outputs 5V to gate
- Source pin connected to ground
- So gate sees 5V relative to source – should be fine?!
Kept poking with multimeter probes. Accidentally shorted drain to gate. Fried MOSFET #3. Cursed at ceiling.
Took coffee break. Felt dumb.
Suddenly remembered: Battery negative connected to Arduino ground? Pulled messy wires apart – nope. Motor battery completely floating. Facepalmed hard.
Soldered all grounds together – MOSFET source, battery negative, Arduino ground. Motor spun like crazy!
Made victory sound scared the cat. MOSFET getting warm though. Stuck small heatsink with thermal tape. Good enough for testing.
Final thoughts: 1RFZ44N works but only if you connect grounds properly and don’t forget resistors. Component itself is dirt cheap but fragile like glass. Wouldn’t use for serious projects.
Wasted whole afternoon but learned something. Garage still messy. Cat still judging me.