Light Dependent Resistor Photoresistor LDR: gl5516 vs gl5506

Question

What is the difference between gl5516 and gl5506? (in a SIMPLE way)

Answer 1

The GL5506 has a significantly lower resistance for a given amount of light compared to the GL5516 AND, in dark conditions the resistance of the GL5516 is significantly higher in resistance (as you would expect). Now go look for the data sheets and read them.

Answer 2

Light dependent resistors (LDRs) today are not that complicated. Designed originally to help count "bottles and/or cans" passing by a moving flow at production factories, they soon lost favor as the light which would trigger the counting reacted to reflections off of the line being counted. Audio response loudness detection is but one use for LDRs over the years.

• As of the 1970s, being paired in an enclosure facing a red LED, to our eyes, this response is desired for audio level threshold detection. Being 540nm (nanometers) sensitive, red is the spectrum they are usually paired with - however, as of the 1990s, 3mm LEDs are much brighter and illuminate quicker on most LDRs.
• Audio level compression (ALC) quit using the LED and LDR combination once record players started using "moving magnet pre-amps" because the records themselves had too much variable clicks, pops and rumbling interference to deal with.
• The use of DBX-118's became the standard very quickly by the 1980s. In the 1980s they were used to "reconstruct video brightness stabilization" for satellite transmitted broadcasts in scrambling communications world wide.
• The full and dark resistance levels are used in matching the amplifier's input standards. The GL5506 and the GL4506 both operate from 5000 to 200,000 ohms - while the GL5516 and the GL4516 operate from 10,000 to 500,000 ohms.
• The voltage levels references are from a time when tubes were used for amplification applications. The time attack/release details are pre-set and cannot be changed. For computer and robotic light detection with Arduino projects, unlike sound/sonar, the only limitations are their light sources. In those designs, the programs themselves can be adjusted for each LDR response. Heat is actually not an issue so, yes - you can use them to see if your refrigerator's light, inside, does go off when the door is closed.