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How can an offline LED driver last 20 years? – The Cu-Beam light is certainly the best LED light that the worldwide market has to offer. However, the spec says that the LED lasts 180,000 hours (20 years) and that the offline LED driver that ships with it lasts as long as the LED (ie, 20 years). The offline LED driver is said to last the 20 years because of having big heatsinks and special capacitors. Surely no offline LED driver can last 20 years? Read more
Offline switch mode EV chargers should be made of paralleled <3kW modules? – It’s very notable how high power (3kW) switch mode Electric Vehicle chargers always use multiple paralleled modules, each with power less than 3kw, instead of using one single high power module. Do you agree that switch mode EV chargers should be made up of multiple modules in parallel, all below 3kw each? Read more
Layout critique LT3741 DC-DC buck converter – I’m a junior electrical engineer who got the task to design a constant current source. Since I’m not really experienced in PSU design I’d like you to
criticize my layout. The schematic is basically the same as the one on the first page of the LT3741 datasheet
The PCB will have 2 layers,70u copper and is 60mm diameter. Have I made any big mistakes? Read more
DC motor vs AC motor – I wonder when it is suitable to use a DC motor and when it is suitable to use an AC motor? The speed that the machine will go is variable between 0-10 meter/minute. The speed now for the brush is: motor gives 182 turns/min and we have a gear on 66:1 => 182/66=2.76 turns/min and volt We give it 42 V => 116 turns/min max. So it should vary between 0 – 116turns/min. Read more
Choosing the right motor for project – My project is basically a pan/tilt gimbal that will have a mannequin head on the top that is controlled wirelessly by a head tracker – so as your head moves the mannequins head should also follow suit. I don’t foresee the head weighing more than a couple pounds, though not sure of the gimbal weight. I don’t know which motor to use. The motor should keep pace with mannequin no matter how fast the user moves their head, slow, to very fast – basically replicating the user’s head movement. Read more
Measuring AC voltage between 2 phases – I am having 3 phase supply – r y b n. The voltage across r and neutral is 205; voltage across y and neutral is 190; the voltage across b to neutral is 220v.
What is the voltage between r and y terminals – the line-to-line voltage? Read more
SSTC (Solid State Tesla Coil) half bridge PCB design – I am making an SSTC (Solid State Tesla Coil). That’s a device which converts mains power (directly powered from 230V socket) to high voltage (100kV +). The halfbridge is made of two IGBTs which are switched at around 200kHz (or less, I might go for 100kHz or so in the end). I’d like to design my single-sided PCB well but I don’t know where to start.
1. Can anyone recommend me any online readings, sites, videos, PDFs or ebooks related to high power/frequency PCB design?
2. Has anyone here designed a halfbridge single-sided PCB for Tesla or induction heater and can share his layout?
3. Please take a look at my halfbridge schematic and layouts. Read more
Connecting zener diode in series with AC 440v line – The attached circuit works fine if the applied voltage is above the zener diode voltage (68V). The led lights up. My question is will the zener withstand high voltage 440V AC? Read more
SG3525 switching frequency deadtime – I’m trying to design an inverter and am about to order components. I am using the SG3525 at the push-pull converter stage with a 50 kHz switching frequency. I initially planned to have a 48% duty cycle for each pulse but I am worried that this is not enough dead time. Could anyone advise if this is ok? I am considering recalculating for 45% but would rather not if this is a pointless exercise. Read more
Isolated DC/DC design – I need an isolated DC/DC power supply, input 9V – 36V, output 15V 0.4A. Unfortunately, I don’t have experience in SMPS. I need help to understand which topology is the best for my case. The end user wants to use this transformer. It has a turns ratio of 1:1. Read more