---
title: "DigiCirq (@digicirq) | Hashnode"
description: "Electronics, explained one circuit at a time. Written guides to every DigiCirq video. Read the latest articles by DigiCirq on Hashnode."
url: "https://hashnode.com/@digicirq"
---

@digicirq

# DigiCirq

@digicirq · Joined November 2026

Electronics, explained one circuit at a time. Written guides to every DigiCirq video.

### [WhatsApp Ticks Explained: One Grey, Two Grey, Two Blue, and Why Blue Doesn't Always Mean Read](https://digicirq.hashnode.dev/whatsapp-ticks-explained-one-grey-two-grey-two-blue-and-why-blue-doesn-t-always-mean-read?utm_source=hashnode&utm_medium=feed)

One tick is the server, two is the phone, blue is the eyes. How delivery and read receipts travel, why two grey ticks sit for days, how to read without blue.

5 min read · [digicirq.hashnode.dev](https://digicirq.hashnode.dev/whatsapp-ticks-explained-one-grey-two-grey-two-blue-and-why-blue-doesn-t-always-mean-read?utm_source=hashnode&utm_medium=feed)

[45m ago](https://hashnode.com/posts/whatsapp-ticks-explained-one-grey-two-grey-two-blue-and-why-blue-doesn-t-always-mean-read/6af413ccc341a4521a037cba)

### [What Does "Rate Limited" Mean? (Twitter, Discord, APIs and the 429 Error Explained)](https://digicirq.hashnode.dev/what-does-rate-limited-mean-twitter-discord-apis-and-the-429-error-explained?utm_source=hashnode&utm_medium=feed)

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.

5 min read · [digicirq.hashnode.dev](https://digicirq.hashnode.dev/what-does-rate-limited-mean-twitter-discord-apis-and-the-429-error-explained?utm_source=hashnode&utm_medium=feed)

[48m ago](https://hashnode.com/posts/what-does-rate-limited-mean-twitter-discord-apis-and-the-429-error-explained/6af41315efe44f37819b4b73)

### [How Does an Arduino Actually Work? From Your Sketch to One Pin Going HIGH](https://digicirq.hashnode.dev/how-does-an-arduino-actually-work-from-your-sketch-to-one-pin-going-high?utm_source=hashnode&utm_medium=feed)

What happens between digitalWrite(13, HIGH) and 5 V on a pin: the compiler, the upload, the bootloader, the ATmega328P, and the one bit in one register that does it.

6 min read · [digicirq.hashnode.dev](https://digicirq.hashnode.dev/how-does-an-arduino-actually-work-from-your-sketch-to-one-pin-going-high?utm_source=hashnode&utm_medium=feed)

[51m ago](https://hashnode.com/posts/how-does-an-arduino-actually-work-from-your-sketch-to-one-pin-going-high/6af41250ca39a8bd72dfe9ee)

### [What Is a Flip-Flop Circuit? SR, D, JK and T Flip-Flops Explained](https://digicirq.hashnode.dev/what-is-a-flip-flop-circuit-sr-d-jk-and-t-flip-flops-explained?utm_source=hashnode&utm_medium=feed)

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 do.

5 min read · [digicirq.hashnode.dev](https://digicirq.hashnode.dev/what-is-a-flip-flop-circuit-sr-d-jk-and-t-flip-flops-explained?utm_source=hashnode&utm_medium=feed)

[55m ago](https://hashnode.com/posts/what-is-a-flip-flop-circuit-sr-d-jk-and-t-flip-flops-explained/6af4118ac9ced2dc8a7ffff1)

### [What Is a Decoupling Capacitor? (Values, Placement, and Why Your Chip Resets Without One)](https://digicirq.hashnode.dev/what-is-a-decoupling-capacitor-values-placement-and-why-your-chip-resets-without-one?utm_source=hashnode&utm_medium=feed)

A decoupling capacitor is a tiny local battery beside a chip power pin. Why 100 nF, why it must sit close to the pin, which leg goes to ground, decoupling vs bypass.

5 min read · [digicirq.hashnode.dev](https://digicirq.hashnode.dev/what-is-a-decoupling-capacitor-values-placement-and-why-your-chip-resets-without-one?utm_source=hashnode&utm_medium=feed)

[56m ago](https://hashnode.com/posts/what-is-a-decoupling-capacitor-values-placement-and-why-your-chip-resets-without-one/6af4111f4445d959e76ba9d1)