As far as I know the lifetime of a LED depends on its junction temperature. The lifetime approx. doubles with each 10 degrees decrease of junction temperature.
The junction temperature, at its turn, depends at the one side of the ambient temperature and at the other side of the internal...
For a light switching application we use a PCB relay with a high inrush current rating (120A/20ms).
We frequently get questions from our customers, because they use lighting ballast (ECG's) with different current-time specifications for the inrush current.
Is there any theoretical model to...
Thank you all for your useful comments and tips!
ScottyUK: yes, I mean half-wave rectified (bad translation from my native language)
itsmoked: thank you for the link; these are the formulas I was looking for. But I do not fully understand the parameters:
- IAC: Rms current the transformer needs...
A power transformer has an output rating in VA. If I load the transformer with a single side rectified circuit with a big electrolytic capacitor for smoothing and a DC load, the power factor of the transformer load will be very bad. Is it allowed in this case to load the transformer with an...
Ok yes, I forgot to tell part of the story. The ventilation unit applies 'balanced ventilation', so that forward and return air have equal quantity. The air flow has been measured recently, and both flows were equal in air quantity. I have calculated the Effectiveness as: (T_supply_indoor -...
At our company building we have a heat recovery ventilation unit with cross flow heat exchanger. We have calculated the Effectiveness of the heat exchanger by measuring the outdoor inlet air temperature, the indoor supply air temperature and the indoor return air temperature. I measured an...
Thank you for all your useful responses.
One complicating aspect is that we sell only the product itself and that our customers build it (together with other components and installation materials) into a control panel (cabinet).
We specify our product at a maximum ambient temperature of 50...
We are working on development of a new electronic product which is mounted in a control panel. We have run some thermal simulations to predict the thermal behavior of the product in the panel. The panel is a fully closed cabinet, so there is no airflow and only natural convection occurs.
We have...
