CircuitLens المجلة
مقالات إلكترونيات قصيرة، مقال كل يوم، مع أمثلة محلولة ونصائح عملية للورشة.
2026-11-02دايودات زينر كمرجع للجهد: ما تجيده وأين تقصريمكن لدايود زينر ومقاومة واحدة تكوين خط جهد مرجعي سريع على طاولة العمل. إليك طريقة تحديد قيمته بأرقام حقيقية، وأين ستظهر حدود الانحراف والتحميل.
2026-11-01What a Flyback Diode Protects, and Why It Sits Across the CoilA flyback diode across a relay or solenoid coil stops the large voltage spike that appears when the current is switched off. Here is how it works and how to size and place one.
2026-10-31ترانزستور BJT مقابل MOSFET كمفتاح: اختيار الأنسب على طاولة العملمقارنة عملية على طاولة العمل لكيفية تصرف ترانزستورات الوصلة الثنائية القطب BJT وترانزستورات MOSFET كمفاتيح، مع مثال محلول لقيادة حمل 100 mA من طرف متحكم دقيق بجهد 3.3 V.
2026-10-22Why a Diode's Forward Voltage Isn't One Fixed NumberThe 0.7 V rule of thumb hides a real spread. Current, temperature, and diode type all shift the forward drop, and a worked example shows how much it matters on the bench.
2026-10-21قراءة ورقة بيانات MOSFET: Vgs(th) مقابل جهد البوابة الذي تطبقه فعلياًVgs(th) هو النقطة التي يبدأ عندها MOSFET بالتوصيل، لا النقطة التي يصل عندها إلى التشغيل الكامل. إليك طريقة مقارنته بجهد البوابة على طاولة عملك لتجنب قطعة تسخن بشدة.
2026-10-20Why a Crystal Oscillator Needs Load Capacitors to Hit Its FrequencyA crystal's rated frequency assumes a specific load capacitance. Here is how the two capacitors around it set that load, with a worked example and bench checks.
2026-10-19Inductors Resist Changes in Current, Not Current ItselfAn inductor does not oppose current; it opposes how fast current changes. That one idea explains coil kick, slow turn-on in circuits, and why a switch can get zapped.
2026-10-17What ESR Means for a Capacitor and Why It Matters in Switching SuppliesEquivalent series resistance decides how much a capacitor really smooths a switching supply's output. A worked example shows why a cap that looks fine on paper can still ripple badly.
2026-10-16Reading a Resistor's Colour Code Without a Chart: The Logic Behind the BandsOnce you know the pattern, a resistor's colour bands can be decoded in seconds. Here is the reasoning behind the code, a worked example, and bench habits that prevent misreads.
2026-10-16Electrolytic vs Ceramic vs Film Capacitors: Picking the Right DielectricElectrolytic, ceramic, and film capacitors look interchangeable on a breadboard until they aren't. Here is how their dielectrics change capacitance, polarity, loss, and stability.
2026-09-27Why Decoupling Capacitors Sit Close to the IC, Not Just 'Somewhere on the Rail'Placement matters as much as value: a decoupling cap a centimeter too far away can fail to do its job because of the wire it's connected through.
2026-09-26How a Multimeter Actually Measures Resistance (and Where It Can Mislead You)Your meter doesn't sense resistance directly—it injects a tiny current and measures a voltage. Knowing this explains most of the odd readings you get in-circuit.
2026-09-25Ohm's Law in Practice: Reading a Resistor Under Real-World TolerancesOhm's Law gives you a clean prediction, but real resistors and meters wander from the ideal. Here's how to account for tolerance without second-guessing your bench work.