{"product_id":"2004a-lcd-character-display-module-20x4-5v-blue-backlight","title":"2004A LCD Character Display Module 20x4 5V Blue Backlight","description":"\u003ch2\u003e2004A LCD Character Display Module — 20×4 Lines, 5V, Blue LED Backlight\u003c\/h2\u003e\n\n\u003cp\u003eThe \u003cstrong\u003e2004A (J204A) LCD Character Display Module\u003c\/strong\u003e is a versatile 20-column × 4-row alphanumeric screen ideal for microcontroller projects, Arduino builds, Raspberry Pi setups, DIY electronics, lab instruments, and embedded systems. Running at a clean \u003cstrong\u003e5V supply\u003c\/strong\u003e, it delivers crisp, easy-to-read characters on a vivid \u003cstrong\u003eblue LED backlit panel with white text\u003c\/strong\u003e — perfect for both indoor enclosures and prototyping breadboards.\u003c\/p\u003e\n\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003e20 columns × 4 rows\u003c\/strong\u003e of character display — plenty of space for sensor readings, menus, status messages, and data output\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e5V operating voltage\u003c\/strong\u003e — compatible with Arduino, Raspberry Pi, PIC, AVR, STM32, and most common microcontrollers\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBlue LED backlight\u003c\/strong\u003e with white characters for high-contrast readability in low-light environments\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eStandard 16-pin HD44780-compatible interface\u003c\/strong\u003e — works with virtually all LCD libraries (I2C adapter compatible)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLCM (Liquid Crystal Module) construction\u003c\/strong\u003e — durable, compact, and easy to mount in project enclosures\u003c\/li\u003e\n  \u003cli\u003eAdjustable contrast via onboard potentiometer (or trimpot on I2C backpack)\u003c\/li\u003e\n  \u003cli\u003eWide operating temperature range — reliable in workshop and lab environments\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTypical Applications\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eArduino \u0026amp; Raspberry Pi hobby projects\u003c\/li\u003e\n  \u003cli\u003eDIY weather stations and sensor dashboards\u003c\/li\u003e\n  \u003cli\u003eHome automation control panels\u003c\/li\u003e\n  \u003cli\u003eIndustrial prototyping and embedded system displays\u003c\/li\u003e\n  \u003cli\u003eEducational electronics kits and STEM labs\u003c\/li\u003e\n  \u003cli\u003eCustom clocks, timers, and measurement displays\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eModel:\u003c\/strong\u003e 2004A \/ J204A\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDisplay Format:\u003c\/strong\u003e 20 characters × 4 lines\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSupply Voltage:\u003c\/strong\u003e 5V DC\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBacklight Color:\u003c\/strong\u003e Blue (LED)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCharacter Color:\u003c\/strong\u003e White\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eInterface:\u003c\/strong\u003e 16-pin parallel (HD44780-compatible)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eController:\u003c\/strong\u003e HD44780 or equivalent\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eVendor:\u003c\/strong\u003e Qme\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eFor guidance on electronics safety and best practices when working with low-voltage display modules, visit the U.S. Consumer Product Safety Commission (CPSC).\u003c\/p\u003e\n\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\n\u003ch4\u003eQ: What microcontrollers are compatible with the 2004A LCD Character Display Module?\u003c\/h4\u003e\n\u003cp\u003eA: The 2004A LCD module uses the industry-standard HD44780-compatible parallel interface, making it compatible with Arduino (Uno, Mega, Nano), Raspberry Pi (via I2C backpack), PIC, AVR, STM32, ESP8266, ESP32, and most other 5V or 3.3V (with logic level shifting) microcontrollers. Popular libraries such as the Arduino LiquidCrystal and LiquidCrystal_I2C libraries support it out of the box.\u003c\/p\u003e\n\n\u003ch4\u003eQ: Can I use the 2004A LCD module with an I2C adapter?\u003c\/h4\u003e\n\u003cp\u003eA: Yes. While the module itself uses a 16-pin parallel interface, you can attach a widely available I2C backpack module (PCF8574-based) to reduce wiring to just 4 pins (VCC, GND, SDA, SCL). This is a popular approach for Arduino and Raspberry Pi builds where GPIO pins are limited.\u003c\/p\u003e\n\n\u003ch4\u003eQ: What does \"20×4\" mean on this LCD display module?\u003c\/h4\u003e\n\u003cp\u003eA: \"20×4\" refers to the display grid: 20 character columns across and 4 rows of text. This gives you 80 total character positions — enough to display multi-line sensor readings, status messages, menu options, and custom data all at once, making it ideal for more information-rich projects compared to smaller 16×2 screens.\u003c\/p\u003e\n\n\u003ch4\u003eQ: How do I adjust the contrast on the 2004A LCD module?\u003c\/h4\u003e\n\u003cp\u003eA: The contrast is adjusted by varying the voltage on pin 3 (VEE\/V0). On most setups, a 10kΩ potentiometer connected between VCC and GND with the wiper going to pin 3 allows you to dial in perfect contrast. If using an I2C backpack, there is usually a small onboard trimpot you can turn with a small screwdriver.\u003c\/p\u003e\n\u003cscript type=\"application\/ld+json\"\u003e{\"@context\": \"https:\/\/schema.org\", \"@type\": \"FAQPage\", \"mainEntity\": [{\"@type\": \"Question\", \"name\": \"What microcontrollers are compatible with the 2004A LCD Character Display Module?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"The 2004A LCD module uses the industry-standard HD44780-compatible parallel interface, making it compatible with Arduino (Uno, Mega, Nano), Raspberry Pi (via I2C backpack), PIC, AVR, STM32, ESP8266, ESP32, and most other 5V or 3.3V (with logic level shifting) microcontrollers. Popular libraries such as the Arduino LiquidCrystal and LiquidCrystal_I2C libraries support it out of the box.\"}}, {\"@type\": \"Question\", \"name\": \"Can I use the 2004A LCD module with an I2C adapter?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Yes. 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