Short animated explainers on how electronics, Arduino, microcontrollers and the apps you use every day really work. Every article is a written guide to one DigiCirq video.https://yhuakim.github.io/https://yhuakim.github.io/digicirq-site/articles/how-an-arduino-actually-works/https://yhuakim.github.io/digicirq-site/articles/how-an-arduino-actually-works/What happens between digitalWrite(13, HIGH) and 5 volts on a pin: the compiler, the upload, the bootloader, the ATmega328P, and the one bit in one register that does it.Mon, 23 Nov 2026 00:00:00 GMTArduino Explainedhow does arduino workhow does an arduino workhow does arduino code workwhat is a microcontrollermicrocontroller vs microprocessoris arduino just c++atmega328parduino uno pinshttps://yhuakim.github.io/digicirq-site/articles/why-your-wifi-slows-down-at-night/https://yhuakim.github.io/digicirq-site/articles/why-your-wifi-slows-down-at-night/Wi-Fi slows at night because you share two things: the air in your building and the cable to your street. How channels, airtime and ISP contention work, and what to fix.Sun, 22 Nov 2026 00:00:00 GMTEveryday Techwifi slowwhy is my wifi slow at nightwifi slow on phone but not other deviceswifi slow iphonewifi slow on laptopspeedtest fast but internet slowwifi slow upload speed2.4 ghz vs 5 ghzhttps://yhuakim.github.io/digicirq-site/articles/whatsapp-ticks-explained/https://yhuakim.github.io/digicirq-site/articles/whatsapp-ticks-explained/One tick is the server, two is the phone, blue is the eyes. How delivery and read receipts travel, why two grey ticks can sit for days, and how to read without blue.Sat, 21 Nov 2026 00:00:00 GMTHow Apps Workwhatsapp ticks bluewhatsapp ticks greywhatsapp ticks explainedwhy does whatsapp only show one ticktwo grey ticks not bluecan someone read a whatsapp message without blue tickswhatsapp read receiptshttps://yhuakim.github.io/digicirq-site/articles/why-your-ups-beeps/https://yhuakim.github.io/digicirq-site/articles/why-your-ups-beeps/A UPS beeps the instant mains fails because it just switched to its inverter. What each beep pattern means, why it beeps after a new battery, and whether to leave it on.Fri, 20 Nov 2026 00:00:00 GMTEveryday Techups is beepingapc ups beepingapc ups beeping continuouslyups beeping after replacing batterywhy is my inverter beepingshould I keep my UPS plugged inback ups 650 beepinghttps://yhuakim.github.io/digicirq-site/articles/what-rate-limited-means/https://yhuakim.github.io/digicirq-site/articles/what-rate-limited-means/Rate limited means you sent requests faster than the service allows, so it refused some. What the 429 error is, how token buckets count, and why apps do it on purpose.Thu, 19 Nov 2026 00:00:00 GMTHow Apps Workwhat does rate limiting meanrate limited twitterrate limited discordrate limiting api429 too many requestsrate limiting algorithmstoken bucketrate limiting with redishttps://yhuakim.github.io/digicirq-site/articles/flip-flops-explained/https://yhuakim.github.io/digicirq-site/articles/flip-flops-explained/A flip-flop is one bit of memory made from two gates that feed each other. How the SR latch holds a value, what the clock adds, and what D, JK and T flip-flops are for.Wed, 18 Nov 2026 00:00:00 GMTDigital Logicflip flop circuitflip flop logic circuitwhat is flip flop circuitsr flip flopd flip flop circuit diagramjk flip flopt flip flopflip flop digital circuithttps://yhuakim.github.io/digicirq-site/articles/decoupling-capacitors-explained/https://yhuakim.github.io/digicirq-site/articles/decoupling-capacitors-explained/A decoupling capacitor is a tiny local battery beside a chip's power pin. Why 100 nF, why it must sit close to the pin, which leg goes to ground, decoupling vs bypass.Tue, 17 Nov 2026 00:00:00 GMTElectronics Basicswhat is decoupling capacitordecoupling capacitor valuesdecoupling capacitor placementdecoupling capacitor vs bypass capacitordecoupling capacitor purpose100nF capacitorhttps://yhuakim.github.io/digicirq-site/articles/why-your-phone-dies-at-15-percent/https://yhuakim.github.io/digicirq-site/articles/why-your-phone-dies-at-15-percent/The charge is still there. Cold raises internal resistance, the camera pulls a surge, voltage sags below the cutoff and the phone shuts down. Why the gauge lies.Mon, 16 Nov 2026 00:00:00 GMTEveryday Techphone dies at 15 percentphone battery cold weatherbattery percentage wronginternal resistancelithium ion batterybattery fuel gaugehttps://yhuakim.github.io/digicirq-site/articles/why-circuit-breakers-trip/https://yhuakim.github.io/digicirq-site/articles/why-circuit-breakers-trip/A 13 A kettle plus a 10 A iron on a 16 A circuit is 23 amps through a wire rated for 16. What heat does in the wall, how the bimetal strip and magnet work.Sun, 15 Nov 2026 00:00:00 GMTEveryday Techcircuit breaker trippingwhy does my breaker tripkettle and iron trip switchbimetallic stripoverload protectionI squared Rhttps://yhuakim.github.io/digicirq-site/articles/how-a-7-segment-display-works/https://yhuakim.github.io/digicirq-site/articles/how-a-7-segment-display-works/A 7-segment display is eight LEDs sharing one pin. Common anode vs common cathode, which segments make each digit, resistor values, and Arduino code.Sat, 14 Nov 2026 00:00:00 GMTElectronics Basics7 segment displayseven segment displaycommon anodecommon cathode7 segment arduino7 segment truth tablehttps://yhuakim.github.io/digicirq-site/articles/how-a-555-timer-works/https://yhuakim.github.io/digicirq-site/articles/how-a-555-timer-works/Inside the 555: three resistors set ⅓ and ⅔ thresholds, two comparators watch a capacitor, a flip-flop makes it blink. Astable and monostable, with formulas.Fri, 13 Nov 2026 00:00:00 GMTElectronics Basics555 timer555 astable555 monostablehow 555 works555 frequency formulaNE555https://yhuakim.github.io/digicirq-site/articles/button-debouncing-explained/https://yhuakim.github.io/digicirq-site/articles/button-debouncing-explained/Mechanical switches bounce for a few milliseconds every press. Here's what that looks like on a scope, and three ways to debounce: a delay, millis(), and an RC filter.Thu, 12 Nov 2026 00:00:00 GMTElectronics Basicsbutton debouncedebouncing arduinoswitch bouncemillis debounceRC debouncecontact bouncehttps://yhuakim.github.io/digicirq-site/articles/pull-up-resistors-explained/https://yhuakim.github.io/digicirq-site/articles/pull-up-resistors-explained/A pull-up resistor gives an input pin a definite voltage when nothing drives it. Why a floating pin reads garbage, what value to use, and pull-up vs pull-down.Wed, 11 Nov 2026 00:00:00 GMTElectronics Basicspull-up resistorfloating inputINPUT_PULLUPpull-down resistorArduino button10k resistor