Engineering English
Input Impedance
Electrical Engineering · Electronics Engineering · Biomedical Engineering · Last updated: July 30, 2026 · How this entry was written
Definition: The impedance measured at the input terminals of a network when no load is connected, determining how the network interacts with a source.
Example in context
“The amplifier’s input impedance must be much higher than the source’s output impedance to avoid signal attenuation.”
“Sinyal zayıflamasını önlemek için amplifikatörün giriş empedansı, kaynağın çıkış empedansından çok daha yüksek olmalıdır.”
Where engineers use it
This term appears when designing cascaded stages, matching networks, and ensuring proper signal transfer. Engineers need it to calculate loading effects and ensure maximum power transfer or minimal distortion.
Synonyms: driving-point impedance
Antonyms: output impedance
In Electronics Engineering
The input impedance of a circuit is the equivalent impedance measured at its input terminals. It determines how much current the circuit draws from the preceding stage.
“The input impedance of the non-inverting amplifier configuration is very high, which minimizes loading on the sensor.”
In Biomedical Engineering
The complex opposition a circuit presents to current drawn from the source connected to its terminals. When it is not far larger than the source impedance, the measured amplitude is attenuated and mismatch converts common-mode voltage into differential error.
“Because dry contacts can exceed one megohm, the buffer needs an input impedance of at least a gigohm to keep amplitude loss below one percent.”
Practice: can you use “Input Impedance” at work?
You are designing a sensor interface. The sensor has an output impedance of 50 Ω; specify the required input impedance of the amplifier to avoid loading errors and explain your reasoning.
Show a model answer
“Determine the input impedance of the circuit looking into terminals A and B.”
“Input Impedance” in 21 languages
| English | Input Impedance |
|---|---|
| Turkish | Giriş Empedansı |
| French | Impédance d’Entrée |
| German | Eingangsimpedanz |
| Spanish | Impedancia de Entrada |
| Chinese | 输入阻抗 |
| Arabic | مقاومة الدخل |
| Portuguese | Impedância de Entrada |
| Russian | Входное сопротивление |
| Japanese | 入力インピーダンス |
| Italian | Impedenza d’Ingresso |
| Vietnamese | Trở kháng đầu vào |
| Hindi | इनपुट प्रतिबाधा |
| Thai | อิมพีแดนซ์อินพุต |
| Indonesian | Impedansi Masukan |
| Korean | 입력 임피던스 |
| Bengali | ইনপুট ইম্পিড্যান্স |
| Dutch | Ingangsimpedantie |
| Swedish | Ingångsimpedans |
| Finnish | Tuloimpedanssi |
| Ukrainian | Вхідний опір |
Frequently asked questions
What does Input Impedance mean in engineering?
The impedance measured at the input terminals of a network when no load is connected, determining how the network interacts with a source. In Electrical Engineering, the term carries a usage-frequency rating of 10/10 in the Engineering English library.
How do you pronounce Input Impedance?
Input Impedance is pronounced /ˈɪnpʊt ɪmˈpiːdəns/ (IPA). The Engineering English app plays audio for the term and checks your pronunciation with speech recognition.
How is Input Impedance used in a sentence?
Example from an engineering context: “The amplifier’s input impedance must be much higher than the source’s output impedance to avoid signal attenuation.”
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