CDS002 LDR 5mm: Specifications, Features, and Selection Guide for SA Projects

Overview: What is a CDS002 5mm LDR?

The CDS002 LDR (Light Dependent Resistor), sometimes referred to as a photoresistor, is a photo-sensitive electronic component that changes its resistance depending on the ambient light level. The specific 5mm variant is a popular choice in hobby, educational, and automation circuits across South Africa due to its affordability, reliability, and general-purpose sensitivity.

This guide details the key electrical specifications, practical features, and use tips for the CDS002 LDR 5mm, based on manufacturer datasheets and local sourcing realities. Whether you're designing a light sensor project, a day/night switch, or need curriculum components for the lab, understanding these specs helps with part selection and reliable circuit design.

Specifications Table: CDS002 5mm LDR

Common Features and Practical Advantages

• Passive, two-lead component - no bias voltage needed
• Wide sensing angle and uniform response over the surface
• Linear-enough for basic light-to-voltage divider circuits (not frequency sensitive)
• Durable and easy to solder or breadboard
• Suitable for signal levels up to 5V (Arduino, Raspberry Pi, PLC analog inputs)

Unlike digital light sensors, LDRs like CDS002 are analog and effective when a simple, continuous monitoring of ambient light is needed. This is valuable for applications without microcontrollers or for straightforward analog circuits.

Typical Applications in South Africa

• Automatic lighting/dusk-to-dawn switches for home/municipal/campus use
• Student electronics kits and school physical science demonstrations
• Non-contact light/obstacle sensors in robotics hobby and competitions
• Panel brightness detection in solar/IoT monitoring setups

Selection Criteria: Key Considerations

• Resistance Range: For most Arduino or analog input projects, the 5-12 kOhm (on, in light) to >1 MOhm (in dark) spec covers a broad spectrum of ambient conditions.
• Body Size: 5mm diameter is a standard fit for breadboards, educational PCBs, and retrofits. Larger LDRs offer more surface area (higher sensitivity), but the 5mm is a balance of response and compactness.
• Response Time: 20-30 ms is more than adequate for "room brightness" sensing, lighting control, and most human-visible changes. If you require millisecond-scale detection, photodiodes may be better.
• Cost & Availability: The CDS002 5mm LDR is low-cost and available from Communica in both single and bulk packs. For schools, lead times are typically less than 3 working days for in-stock items at Samrand or major branches.

Example Circuit (Voltage Divider for Arduino)

A common way to use the CDS002 LDR is in a resistive divider - see the schematic below:

+5V
 |
 [ LDR (CDS002 5mm) ]
 |
 |--------------------> Analog In (A0)
 |
 [ 10kOhm resistor ]
 |
 GND

The junction between the LDR and the 10kOhm resistor can be read by an ADC input pin on typical microcontrollers or PLCs. Adjust the fixed resistor to tune for your expected brightness levels.

Troubleshooting & Local Usage Advice

• Unstable Readings: Shield from stray light and use decoupling where analog circuits are noisy.
• LDR Not Responding: Check for power over-limit (never exceed 100 mW dissipation) or incorrect resistor pairing.
• Lead Times: For bulk education or industrial stock, phone ahead or check branch and trading times for fastest turnaround.

Top Local Brands & Alternatives

Communica's LDR and photo-sensor ranges include not just CDS002 5mm but several alternatives from major brands. You can browse Sensors and Shop by Brand for related offerings, or for specialized optical sensing needs.

Sources

• Sensors Category - Communica
• Vishay Photoresistor Product Datasheet (Typical LDR Specs)
• Photoresistor/LDR Fundamentals
• Branch Collection & Trading Hours - Communica