- What is the main difference between 1~10V dimming and 0~10V dimming regarding applications?2020-08-17
- With 1~10V dimming, the lighting unit can be dimmed down to 10％; with 0~10V dimming, it can be dim down to 0％, or say, dim to “off”.
- How to use ELN-30/60-XXD(P) Dimming function in applications?2020-08-17
- As shown in fig 11&12, an external signal can be applied to “DIM+” and “DIM-.” The signal can be either DC voltage (D Type) or PWM (P Type). By changing the signal levels as shown below, the output current limit can be controlled by the user. Please note, the relationship between external signal and output current level is non-linear. It cannot be used for high precision dimming control.
- What is the definition of IP (Ingress Protection) ratings? And what is MeanWell’s IP68 definition.2020-08-17
- MEAN WELL has incorporated dust proofing and water proofing into majority of its LED power supply design. Mainly based on the international standard IEC60529, detailed descriptions can be found in the following table:
- What is Withstand Voltage？How to measure it？2020-08-17
- Indicates Hi-Pot Test or Electric Strength Test. The input should be shorted together as well as the output before test. The test will proceed under particular loop, such as I/P-O/P, I/P-FG and O/P-FG with certain high voltage value for 1 minute. (The typical leakage current is 25mA when testing with AC)
- What is Ripple & Noise? How to measure it?2020-08-17
- It is the small unwanted residual periodic variation of the direct current (DC) output of a power supply which has been derived from an alternating current (AC) source. The wave form is shown as figure below.
- What are the protection forms of overload/overcurrent?2020-08-17
- When current drawn exceeds the rating of the PSU, the protection circuit will be triggered to protect the unit against overload/overcurrent.
- What is power good and power fail signals and how can use it?2020-08-17
- Some power supplies provide a Power Good signal when they are turned on, and send out a Power Fail signal when they are turned off. This is usually used for monitoring and controlling purpose.
- What is MTBF? Is it distinct from Life Cycle? What is DMTBF?2020-08-17
- MTBF (Mean Time Between Failure) and Life Cycle are both indicators of reliability. MTBF can be calculated by two different methodologies, which are “part count” and “stress analysis”. The regulations, MIL-HDBK-217F Notice 2 and TELCORDIA SR/TR-332(Bellcore) are commonly used to calculate MTBF. MIL-HDBK-217F is a United States military standard, and TELCORDIA SR/TR-332(Bellcore) is a commercial regulation. MEAN WELL utilize MIL-HDBK-217F(Stress Analysis) as the core of MTBF. The exact meaning of MTBF is, after continuously using the power supply for a certain amount of time, the average time that the probability of proper operation is down to 36.8％（e-1=0.368）. Currently MEAN WELL is adopting MIL-HDBK-217F, forecasting the expected reliability through Stress Analysis (excluding fans); this MTBF means the probability of the product can continue the normal work after working continuously up to the calculated MTBF time is 36.8％ (e-1=0.368). If the power supply is continuously used at double the MTBF time, the probability of proper operation becomes 13.5％（e-2=0.135）. Life Cycle is found by using the temperature rise of electrolytic capacitors under maximum operating temperature to estimate the approximate life of the power supply. For example, RSP-750-12 MTBF=109.1K hours(25°C); electrolytic capacitor C110 Life Cycle=213K hours (Ta=50℃)