Hi all,
I have a low-speed motorized turntable that I would like to modify by adding a couple of limit switches (maybe reed switches?) that will kill power (120VAC) to the turntable if it hits either switch. Additionally, I would like to have a push button that will let me override the system...
Are there any sine-wave dimmers that will be a replacement for those noisy triac-based dimmers? The load consists of incandescent lamps of maybe 1500-2000W (120VAC 60Hz). I would like to eliminate some electrical and audible noise for an audio listening room. I suppose I could use variable...
I've been looking at small (something like 18650 size) lithium-ion batteries for a portable application. However, these batteries typically don't want to be charged above a temperature of 45C or discharged above 60C. Does anyone know of a source of other types of batteries that can safely...
I'm designing a battery-operated device that needs a 5V supply that draws microamps when asleep, but about 2Amps when it's awake. If I use a switching regulator, it will be much more efficient when awake, but the current draw when asleep will be higher. If I use a linear regulator, it will be...
Does anyone have any tips or links to info on designing a PWM interface for a DC motor in order to reduce EMI? I've got a tiny fan (less than 50mA current draw). I plan on driving it with a PWM output using a PNP transistor on the high-side. I figured that I would put a backwards diode across...
Does anyone have any good resources for information about global EMC (electromagnetic compliance) requirements? I'm in the USA, but the consumer electronics company that I works for ships products around the world. However, trying to find out what testing is required is painful. There seems to...
If a spread spectrum oscillator is used to clock a DAC or an ADC, I assume that there will be some distortion or noise introduced due to the intentional clock jitter. Is there a way of predicting the amount of additional distortion or noise if you know the spectrum bandwidth of the oscillator...
Does anyone have any suggestions on simple Windows backup software that will just copy certain data directories to a network drive automatically every night?
Thanks,
Glenn
I have a 2.4 GHz application where the chip vendor has provided info on both a chip antenna and a meander antenna implemented as a PCB trace. They said that the range would be about the same with either design. It seems like the chip antenna would take less space and the meander antenna would...
Does anyone know of any app notes or other technical info that compares driving LEDs with PWM vs constant current in regards to efficiency? I have heard that PWM can use less power for the same apparent brightness due to nonlinearities in brightness vs current and in the eye's perception of...
I wanted to get input on the advantages and disadvantages of using copper pours to fill in all unused spaces of outer layers of PCBs with ground in cases where plane layers already exist. It seems to me that there is the possibility of providing additional shielding if there are internal signal...
Anyone have a source suggestion for an off-the-shelf DC-DC converter for an automotive test environment that can take in the "12V" input (probably more like 11V-14.4V and with appropriate load-dump protection) and output +15V (1.8A), -15V (100mA), and +7V (100mA)? It would be nice if it had a...
Are there any repeaters or other methods of retransmitting the US broadcast bands (FM 87.8 to 108.0 MHz, AM 520 kHz–1610 kHz) inside a building? We are testing AM/FM radios, but our building is built of materials that block out all but a few really strong stations.
There is an antenna on the...
I've got a small motor with a 1/4" round shaft that I want to attach to a flat plate to act like a display turntable. What is the name of the coupling that I'm looking for? I figure that there must be some sort of coupling that has something like a setscrew to tighten around the shaft and some...
Does anyone know if there are any particular safety standards that would have something to say about the best way to avoid having a non-rechargeable battery being charged? For example, if I have a circuit that can be powered by a 9V battery or by a plug-in power supply, I want to avoid having...
Does anyone know of any microcontrollers that have a high-speed (480Mbps) USB controller (either host or device) on them? I find a number of them that have a full-speed (12Mbps) USB controller, but I've only found one micro from Cypress that has a high-speed USB device controller. Am I out of luck?
I'm trying to read a few 4-bit rotary DIP switches in a microcontroller in the most economical way possible. I'd like to minimize the number of GPIO pins used so that I don't have to buy a larger chip than absolutely necessary. I thought of two different ways and I wanted to see if anyone had...
Does anyone know of any recognized standards for drawing schematics (circuit diagrams)? For example, on Wikipedia (http://en.wikipedia.org/wiki/Circuit_diagram), it shows a "modern style" of drawing schematic wire junctions, but it does not say if that is from a particular standard.
Or perhaps...
Hey, does anyone know of any alphanumeric displays (something like 16 characters by 2 lines) that will operate from -40C to +85C?
I've looked at LCDs, but the widest range that I've found will go -20C to +70C. That's too bad, because I like their characteristics otherwise (low power...
Does anyone have any suggestions on an LCD character module that can be interfaced with serially? RS232? I2C? I probably need about 16 or 20 characters wide by 2 lines. Are there any off-the-shelf solutions that would be inexpensive (relatively) for a high-volume application? Or do I need to...
