Solar cables are available for indoor and outdoor use for flexible and fixed installations with high mechanical strength in extreme weather conditions. Solar Cable,Red Tuv Solar Cable,Pvc Copper Electrical Solar Cables,Solar Copper Wire Cable Ruitian Cable CO.,LTD. , https://www.rtpowercable.com
The circuit in Figure 1 drives the LED strings via transistors Q1-Q4, which operate as current mirrors. This technique offers the following advantages: eliminates the current-limiting resistors drives groups of dissimilar LEDs requires just one power supply voltage allows each string to operate at a different current and allows the brightness of all the LEDs to be adjusted with one control point (U1's ADJ pin). 
Figure 1. In this LED-drive circuit, a switching converter (U1) and associated components let you mix LED quantities and types.
Transistors Q2-Q4 mirror the current in diode-connected transistor Q1. Note that the Q1 current-set string (LEDs D3-D5) should have an equal or larger voltage than that of subsequent LED strings. (If it doesn't, the current-mirrored strings may not have enough voltage overhead to function properly.) You can easily meet that requirement in the first string, by placing either LEDs with larger forward voltage drops (such as the approximate 2.8V to 3.7V range of white LEDs) , or a greater number of similar LEDs. Then, the subsequent strings with lower voltage burdens can be easily accommodated.
The matched-transistor current mirrors maintain a constant and equal current in all LEDs, regardless of quantity and type. That configuration allows the use of a single power supply and a single point for adjusting LED brightness.
Any power difference between the reference string and a mirrored string is dissipated in the current-mirror transistor for that string: Pmax (transistor) = (VOUT-300mV-VLEDs) × ILEDMAX. The current-sense resistor value is R2 = 300mV / ILEDMAX , where ILEDMAX is the sum of currents from all the strings. (For a comprehensive circuit and parts list, refer to Maxim's MAX1698 EVKit data sheet.)
When driving the same LEDs without the current mirror one can reduce power dissipation in the sense resistor and ballast resistors by substituting a micro-power op amp across the current-sense resistor (Figure 2). That circuit improves efficiency by reducing the resistor values ​​and their associated loss. Gaining up the current-sense signal by approximately 16 allows an equivalent reduction in the value of R2 and the ballast resistors. 
Figure 2. Modifying Figure 1 as shown reduces the overall power dissipation in a standard application.
A typical value for R2 is 15Ω, which represents a loss of 18mW (ie, 20mA2 × 15Ω for each of three resistors). If R2 = R5 = R6 = 0.931Ω, then the resistor power loss drops to 1.12mW. The op amp draws only 20µA maximum, which is a dissipation of 100µW.
A similar version of this article appeared in the October 3, 2002 issue of EDN magazine.
The cables are designed to withstand the harsh environmental conditions that occur in any fixed, mobile, rooftop or building integrated PV installation.
Applications
Solar energy is used to generate photovoltaic (PV) power by capturing sunlight. The energy is used for solar heating and, thanks to energy conversion, it can also be used to generate electricity. As a result, the demand for solar cables is also increasing. Solar cables are interconnecting cables used in photovoltaic power generation. Solar cables interconnect the solar panels and other electrical components of the PV system. Solar cables are designed to be UV-resistant and weatherproof.
Cable construction
Conductor: fine wire tinned copper conductor.
Insulation: UV-resistant, cross-linkable, halogen-free, flame-retardant compound for core insulation.
Core marking: red, black or natural Sheath: UV-resistant, cross-linkable, halogen-free, flame-retardant compound for the insulation sheath.
Cable colour: black or red
Advantages
Solar cable modules operate at high temperatures and are exposed to a wide range of environmental conditions.
These cables need to meet the sunlight resistance and temperature ratings required by the environment.
Solar cables are manufactured for photovoltaic applications.
Both cable types typically contain XLPE insulation and are resistant to sunlight and/or direct burial.
Circuit Drives Mixed Types and
Portable systems often use LEDs of different colors-white for the display backlight, green for keypad illuminaTIon, red for power, etc., and in varying quanTITITIes of each. Typically the LEDs are driven by at least two power supplies, one for "standard "LEDs (red and green) and one for white LEDs (white LEDs require a higher forward voltage.) The keypad and other indicator LEDs each have current-limiTIng resistors.