Search found 9 matches

by [email protected]
Sat Feb 18, 2006 4:39 am
Forum: General Discussion
Topic: Using A/D to detect PWM signal
Replies: 2
Views: 839

Using A/D to detect PWM signal

Since the DC average of a PWM signal is related to the duty cycle of the signal can you input PWM into a A/D detector and have the A/D detect the average voltage? I have a 5volt PWM signal (servo control) that I would like to be able to determine its average voltage with a A/D that is only 3.3v capa...
by [email protected]
Sat Oct 29, 2005 7:11 am
Forum: General Discussion
Topic: A/D Negative Voltage Input
Replies: 1
Views: 748

A/D Negative Voltage Input

If an A/D converter receives a negative input does the digital output remain at zero or can damage to the circuit result.

Thanks
by [email protected]
Tue Oct 18, 2005 8:13 am
Forum: General Discussion
Topic: Altitude sensor suggestions
Replies: 9
Views: 1692

Re: Altitude sensor suggestions

I found another sensor similar to the one Dave showed. Its the MPX4115. This one has a 0 - 5 volts swing from Least to Max pressure. I put a circuit together that I think should work. According to my calculations approximately 85mv of swing will occur on the sensor from 0 to 500 feet. This will decr...
by [email protected]
Sun Oct 16, 2005 3:20 pm
Forum: General Discussion
Topic: Altitude sensor suggestions
Replies: 9
Views: 1692

Altitude sensor suggestions

I am looking for a sensor that will have a varying voltage from 0 to 5 volts in which I can then use an 8 bit A/D converter to determine the altitude. The altitude range would be no more than 500 ft, but with external circuitry I would like to be able to zero the altitude.<p>Any suggestions?
by [email protected]
Fri Oct 07, 2005 6:13 pm
Forum: General Discussion
Topic: LM338 Dissipated Heat
Replies: 16
Views: 3584

Re: LM338 Dissipated Heat

The slow turn on portion of the circuit is actually from the Nuts and Volts magazine from a few months back. The values in the eagle schematic aren't correct at all. I more or less uploaded the schematic so you could see the interconnects. I placed the parts on the design for spacing and such. This ...
by [email protected]
Fri Oct 07, 2005 10:36 am
Forum: General Discussion
Topic: LM338 Dissipated Heat
Replies: 16
Views: 3584

Re: LM338 Dissipated Heat

I have created a screen shot of the eagle PCB for my project. The supply getting hot is the upper supply. The circuitry that is additional is for slow turn on and a LED.<p>As for where I am getting the center tap. The transformer has three output lines. The outer two were the 12.6 AC and taking a me...
by j_pa[email protected]
Wed Oct 05, 2005 5:17 am
Forum: General Discussion
Topic: LM338 Dissipated Heat
Replies: 16
Views: 3584

Re: LM338 Dissipated Heat

The center tap does not provide a voltage high enough. When I activate the relay that energizes the power supply I can not get enough power for the supply to stay on. I have gone as far as setting the power supply to 1.25 volts and slowly bringing it up to achieve the desired 6 volts. As soon as it ...
by [email protected]
Mon Oct 03, 2005 5:07 am
Forum: General Discussion
Topic: LM338 Dissipated Heat
Replies: 16
Views: 3584

Re: LM338 Dissipated Heat

Thanks for the replies. I will change the input from my transformer to the center tap voltage. This should cut the voltage down to 9 and hopefully reduce the heat considerably. Thanks again!
by [email protected]
Sun Oct 02, 2005 7:57 pm
Forum: General Discussion
Topic: LM338 Dissipated Heat
Replies: 16
Views: 3584

LM338 Dissipated Heat

I have a general question about the heat produced by the LM338 TO220 package voltage regulator. I am regulating 18 Vdc down to 6 volts to power the servos of a robotic arm. After running the arm for about 5 minutes the heat sink attached is nearly too hot to touch. I currently do not have any coolin...