T&L Publications

Well it is Valentines Day and everyone probably has a belly full of m&ms....

Edd, you hit the crystal range on the nose, I fogot to mention that in the text. I have done that as well, just not for production boards. That is most likely what we will do. Thanks to all.

Has anyone used a Crystal in a socket in a production unit so the crystal can be removed and changed in value? The crystal will run a TDA5051 Power line modem interface.

.... for more prototype testing.....


will doooooo.

I have an application where we want the user to select an oscillation frequency with jumpers or dip switches. I want 8 frequencies, spaced 300Khz apart starting at 7.3728Mhz and ending at 9.4728Mhz. I prototyped with the LTC1799 from Linear Technologies. It uses a single resistor to create the frequ...

RTK GPS is the most accurate, <1cm but is the most expensive and can be used by anyone. You have 1 base and 1 rover and X,Y,Z is all very precise. SA is off and doesnt' affect RTK anyway. 1138, I have experimented with what you are asking and no, it does not yield you any more accuracy. A WAAS based...

Great answers! I am still absorbing it all. Philba, I am currently using an H11AA1 on this project to give me a relative voltage level as you described. That works fine and I allow some user settings to tweek it. I was looking at getting a way to display the actual voltage level. I will look more at...

I am thinking of a .08VA transformer, half wave rectified and a 5vdc Zener and filter cap. As the AC side varies, I want to get a 0-5 vdc voltage level. I want to know voltage for a PIC processor A/D input. Has anyone done this before just to measure AC main line voltage? <small>[ January 25, 2006, ...

Thanks, I am going to try the AD5290, I ordered the evaluation kit from Analog Devices.

What would be the easiest way to use a PIC to vary the amplitude of an AC sin wave that is about 8Vpp and 1KHz? I need to vary the amplitude in at least 256 steps. I thought digital potentiometers might do it but I am not ANALOG enough to come up with a clean design. I always want the reference sign...

I know that http://www.tern.com/ceye.htm makes the Ceye that is a camera, micro and flash card all in one....

Jolly Roger,

Could you expand on your drawing a little? It is very close to what I would like to do for my project except I need to shut the battery off if there is no AC and the battery is low. I wouldn't mind a relay even though that will drain the battery faster. Thanks.

I am going to use a AC/DC power supply adjusted to 14V dc. I will have a 12V lead acid battery for backup. I am going to use the device below to charge battery when AC is on, switch over to the battery when it loses AC and cut the battery off when it gets low....<p> http://www.powerstream.com/DC-UPS...

I am looking for a 12V 1 amp DC power supply, DIN rail mounted that will also charge a Lead-Acid battery and switch to battery when AC is lost and shuts down the battery backup if voltage drops < 10Vdc. Does anyone know of a source for these? It must be UL listed. Thanks.<p>[ October 12, 2005: Messa...

All my projects are of the "Horse Shoes" variety. As long as the relay shuts off at some point and prevents damage to the battery. I am going to try the zener and see what happens. Thanks.

I found a power supply that works from AC, outputs 12vdc, charges a lead-acid battery and switches over to battery when the AC is lost. The only thing it does not do is cut the battery off after the voltage gets too low (10V maybe). Does anyone have a simple circuit to cut the battery off OR a bette...