Amp Nerd https://validator.w3.org/feed/docs/rss2.html Blog A Frequency Response Curve Depends on the Load You Tested With A Logic Analyzer Shows You Bits—It Cannot Show You Volts A Scope’s FFT Is Not a Spectrum Analyzer—Know the Difference Auto Trigger Draws a Trace Even When Nothing Is Triggering A 10x Probe Does Not Just Shrink the Signal—It Changes Loading An Uncompensated Probe Lies About Every Square Edge You See Scope Bandwidth Is Not a Cutoff—It Is Where Signals Already Sag An Open Current Transformer Secondary Is a Hazard, Not an Idle Coil A Rogowski Coil Outputs a Derivative, Not a Current A Clamp That Reads DC Works on a Different Principle Than One That Does Not Swapping Two Wires Reverses a Motor—A Meter Will Not Warn You A Plug-In GFCI Tester Can Fail a Circuit That Is Wired Correctly Continuity Proves a Path Exists—Loop Impedance Proves It Can Clear a Fault Matching Supply Voltages Does Not Match Logic Thresholds A Ground Rod’s Resistance Is Not Something a Multimeter Can Read Home An I2C Bus Has a Capacitance Budget You Can Overspend A Pull-Up Value Trades Rise Time Against Wasted Current A Voltage Reference Drifts Long After You Calibrated It Aliasing Does Not Announce Itself—It Looks Like Real Data A Megohmmeter Reading Drifts with Time, Temperature and Moisture A Thermocouple Measures a Difference, Not an Absolute Temperature Duty Cycle Depends on Where the Meter Decides a Pulse Begins A Multimeter’s Capacitance Range Cannot Judge a Bad Capacitor AC and DC Coupling Show You Two Different Halves of a Signal Your Ammeter Steals Voltage from the Circuit It Measures An Unfused Current Input Turns a Wrong Probe Into an Arc A Meter’s Voltage Rating Alone Does Not Tell You Where It Is Safe Connecting 3.3V and 5V Logic Is Not Always a Direct Wire Effective Number of Bits Is the Figure That Tells the Truth A Temperature Probe’s Shape Changes the Number It Reports More Bits on an ADC Does Not Mean a More Accurate Reading A Crystal Runs at the Frequency Its Load Capacitance Chooses An Optocoupler Transfers Less Current as the Years Pass A Schottky Trades Forward Drop for Leakage That Grows Hot A Zener Is a Reference Before It Is a Power Supply A Frequency Reading Is Only as Good as the Meter’s Timebase Surge Protectors Are Not Interchangeable—Three Devices, Three Jobs A Saturated Transistor Is Not a Transistor Amplifying Harder Transistor Gain Is a Range, and Your Design Should Not Need It Gate Charge, Not Gate Capacitance, Sets Your Switching Loss Every MOSFET Contains a Body Diode You Did Not Design In Diode Test Mode Does Not Read Resistance—It Reads Forward Drop A MOSFET’s On-Resistance Climbs as the Device Heats Up Absolute Maximum Ratings Are Limits, Never Operating Points LoZ Mode Is Not a Better Voltmeter—It Is a Deliberate Load Thermal Paste Is a Gap Filler, Not a Heat Conductor Upgrade A Heatsink Rating Assumes Airflow You May Not Actually Have A Meter Can Read Voltage on a Wire That Is Not Live