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I'll be requesting the 500mA and most likely keep it limited to 400mA to be on the safe side. The problem is that these super capacitors act like a short circuit when empty therefore I need to limit the current to 400-500mA.
The USB port provides 100mA. You can request up to 500mA in software which I have done. But most modern USB ports dont care about the requests and some even allow you 1Amp without shutting down. I find most allow up to about 500mA before shutting down.
All I need is something to keep it...
Would you recommend an active current limiter using transistors? If so , what would you recommend? The main reason for the 500mA limiter is to stop the USB port from shutting itself down.
Charging super capacitor with USB - current limiter?
I have a torch that is powered by 2 50Farad Super Capacitors in Series. I use the USB port of a PC to charge the super capacitors using a 10ohm resistor to limit the possible maximum current (5V/10Ohms) to 500mA.
The torch charges up nice...
I have a pair of 50F 2.7V capacitors in series. I charge them up to 5V.
I then have another pair of 50F 2.7V capacitors at zero to 0.5volts. i.e. almost fully discharged.
I wish to use the first pair of caps to charge up the second pair. I do so by connecting them in parallel. There is an...
My problem is as follows:
I have 1000 marbles labelled M1 to M100 (10 of each M number)
Each marble has a different mass, but generally the higher the number, the higher the mass. It is possible for a lower number to have a mass greater than a higher number, but not likely.
Someone packs up...
You need the camera to always be fixed in one orientation. Then compare a picture with no trucks in, to one with trucks in by subtracting the one from the other. Use a loose comparison and you will find that most of the pixels that have changed, belong to the truck.
Use a number of different...
bh1415 fm transmitter
Does anyone know what the best circuit configuration is for this device? I've seen a few different configurations, especially around pin 9, and the PLL section.
Here are some of the configurations I've found. Which one would you say is best?
bh1415 amplifier
I have a transmitter based on the BH1415 chip. What would your suggestions be for boosting the small RF output to 100mW output. The device is intended for a large farm in Namibia (2km range), where the main house must communicate with the worker houses - using a regular FM...
I would like to make a device that can transmit an 4 Byte (32 Bit) code to a central receiver, a distance of about 300 metres.
The purpose of this is to position sensors areound a small farm. The sensors are just ON or OFF. When they are OFF, nothing is transmitted at all - the circuit is...
matching pad 50 to 75 ohm
What Monolithic or other amplifier would you recommend for the final stage?
Added after 2 minutes:
Sorry, My desired output is 100mW
50 ohm vs 75 ohm
I would probably use the pi attenuator as the 1.57 Ohm resistor would be difficult to come by, unless I use some resistors in parallel.
If I put the -7dB output into the Pi attenuator, then I'll have say -13dB, which gets fed iinto the Mar-8asm chip. The gain on the Mar-8asm...
75 ohm to 50 ohm
Is there a way of doing it without using a transformer? I hear the BH1415 burns out after about an hour if I put the 75 Ohm output directly to a 50 Ohm load.
I am thinking of amplifying it using a Mar-8ASM chip.
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