| Table, look-up | Look-up tables |
| Table, truth | Digital signals and gates |
| Tachogenerator | Tachogenerators |
| Tachometer | Tachogenerators |
| Tank circuit | Voltage regulation |
| | An electric pendulum |
| | Simple parallel (tank circuit) resonance |
| | Resonance in series-parallel circuits |
| | Inductor-capacitor "tank" circuit |
| Tantalum capacitor | Practical considerations |
| Tap switch | Winding configurations |
| TE mode | Waveguides |
| TEM mode | Waveguides |
| temperature coefficient | pn-Junction as Temperature Sensor |
| Temperature coefficient of resistance | Conductor and Insulator Tables |
| | Temperature coefficient of resistance |
| Temperature compensation, strain gauge | Strain gauges |
| temperature sensor | pn-Junction as Temperature Sensor |
| temperature switch | Switch types |
| Temperature, cr | Conductor and Insulator Tables |
| Tera | Metric notation |
| Terminal block | Building series-parallel resistor circuits |
| Terminal strip | Building simple resistor circuits |
| | Building series-parallel resistor circuits |
| | A Very Simple Circuit |
| terminal, "ring" lug | Automotive alternator |
| tesla (unit) | Magnetic units of measurement |
| Tesla coil | Special transformers and applications |
| Test lead | Safe meter usage |
| tetanus | Physiological effects of electricity |
| tetrode | Nonlinear Conduction |
| Tetrode tube | The tetrode |
| | Depletion-type IGFETs |
| Text editor | Computer simulation of electric circuits |
| Theorem, DeMorgan's | Digital logic functions |
| Theorem, Maximum Power Transfer | Maximum Power Transfer Theorem |
| Theorem, Millman's | Millman's Theorem |
| | Millman's Theorem revisited |
| Theorem, network | Introduction to network theorems |
| Theorem, Norton's | Norton's Theorem |
| Theorem, Superposition | Superposition Theorem |
| | Three-phase power systems |
| | Circuit effects |
| Theorem, Thevenin's | Thevenin's Theorem |
| | Complex circuits |
| thermal runaway | Current Mirror |
| | JFET Current Regulator |
| thermal runaway, bBJ | Feedback |
| thermal voltage, diode | Diode Characteristic |
| Thermocouple | Thermocouples |
| | Bias Current |
| | Thermoelectricity |
| Thermoelectricity | Thermoelectricity |
| Thermopile | Thermocouples |
| Thevenin's Theorem | Thevenin's Theorem |
| | Complex circuits |
| | Special transformers and applications |
| three input adder | Full-Adder |
| Three-phase | Three-phase power systems |
| three-phase bridge rectifier | Rectifier circuits |
| Three-wire DC system | Three-phase power systems |
| Throws, switch | Contact "normal" state and make/break sequence |
| Thyratron | Ionization (gas-filled) tubes |
| Thyratron tube | Gas discharge tubes |
| Thyristor | Ionization (gas-filled) tubes |
| | The Shockley Diode |
| Timbre | Introduction |
| Time constant | Voltage and current calculations |
| | Capacitor Charging and Discharging |
| Time constant equations | Time constant equations |
| Time constant formula | Voltage and current calculations |
| time delay relay contact | Time-delay relays |
| Time domain | Waveform analysis |
| Time-domain reflectometer | Finite-length transmission lines |
| timer | Time-delay relays |
| | The 555 IC |
| | Monostable Multivibrator |
| TM mode | Waveguides |
| TO-18 | Package TO-18 |
| TO-254AA | Package TO-254AA |
| TO-3 | Package TO-3 |
| TO-39 | Package TO-39 |
| TO-5 | Package TO-5 |
| TO-66 | Package TO-66 |
| TO-72 | Package TO-72 |
| toggle switch | Switch types |
| Token ring | Extended-distance networks |
| token-passing protocol | Network protocols |
| toroidal core inductor | Factors affecting inductance |
| torque | Power in electric circuits |
| Total internal reflectance | Optical data communication |
| Totalizer | Differentiator and integrator circuits |
| Trace, printed circuit board | Building simple resistor circuits |
| Tracking ADC | Tracking ADC |
| Transconductance | Voltage-to-current signal conversion |
| | Active-mode operation |
| Transconductance amplifier | Voltage-to-current signal conversion |
| transducer | Physiological effects of electricity |
| | AC Instrumentation Transducers |
| transductor | Special transformers and applications |
| Transform function, definition of | Algebra Reference |
| Transform, Fourier | Square wave signals |
| transformer | Mutual inductance |
| | Mutual inductance and basic operation |
| | What is alternating current (AC)? |
| | Introduction |
| | Sensitive voltage detector |
| transformer core, laminated | Energy losses |
| transformer core, powdered iron | Energy losses |
| transformer coupling | Input and output coupling |
| Transformer inrush current | Inrush current |
| transformer isolation | Electrical isolation |
| Transformer ratio | Step-up and step-down transformers |
| Transformer, ferroresonant | Voltage regulation |
| transformer, homemade | Build a transformer |
| transformer, peaking | Core saturation |
| Transformer, step-down | Step-up and step-down transformers |
| Transformer, step-up | Step-up and step-down transformers |
| Transformer, variable | Winding configurations |
| | AC Instrumentation Transducers |
| Transient | Electrical transients |
| transistor | Superconductivity |
| | Voltmeter impact on measured circuit |
| | Multimeters |
| | pH measurement |
| | Other waveshapes |
| Transistor, field-effect | Voltmeter impact on measured circuit |
| | pH measurement |
| Transistor, junction field-effect | Static electricity sensor |
| transition temperature | Superconductivity |
| transmission line | A 50-Ohm Cable? |
| Transmitter | Voltage signal systems |
| Triangle wave | More on spectrum analysis |
| | AC Waveforms |
| Trigonometric derivatives | Calculus Reference |
| Trigonometric equivalencies | Trigonometry Reference |
| Trigonometric identities | Trigonometry Reference |
| trimpot | Potentiometer |
| Triode tube | The triode |
| | Gas discharge tubes |
| | Depletion-type IGFETs |
| Triplen harmonics | Harmonics in Polyphase Power Systems |
| | Harmonic phase sequences |
| Tristate output | Special-output gates |
| Troubleshooting | Troubleshooting -- Theory and Practice |
| | Component failure analysis |
| True-RMS meter | Measurements of AC magnitude |
| Truth table | Digital signals and gates |
| truth table to Karnaugh map | Karnaugh maps, truth tables, and Boolean expressions |
| TTL | The NOT gate |
| tube | Introduction |
| Tube, discharge | Ionization (gas-filled) tubes |
| Tube, vacuum | Voltmeter impact on measured circuit |
| | Winding configurations |
| tube, vacuum or electron | Conventional versus electron flow |
| tuner circuit | Resonant filters |
| Tuner circuit, radio | Applications of resonance |
| tunnel diode | Nonlinear Conduction |
| | Tunnel Diodes |
| | Tunnel Diode |
| tunneling transistor | Double-Layer Tunneling Transistor |
| Turing machine | Finite-state machines |
| Twin-T circuit, differential capacitance | AC Instrumentation Transducers |
| Twisted pair cable | Introduction |
| two input adder | Half-Adder |
| Two's complement | Negative binary numbers |