ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat Box
Recent Posts
Happy Thanksgiving
by gfretwell - 11/26/20 08:52 PM
Insulated Tools: A Waste of Money?
by HotLine1 - 11/26/20 12:28 PM
Ground fault remover :-)
by NORCAL - 11/26/20 08:13 AM
Work Gloves?
by sabrown - 11/25/20 01:54 PM
What does your work place look like?
by Lostazhell - 11/25/20 02:56 AM
New in the Gallery:
Facebook follies, bad wiring
FPE in Germany pt.2
Who's Online Now
0 registered members (), 18 guests, and 16 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
help on basic circuits #128844 02/19/04 08:46 PM
Joined: Jan 2004
Posts: 1
B
battlestar Offline OP
Junior Member
Hi, I'm pretty new to the world of electronics, and I'm attempting an small project that I need some help upon.

1. If there are three wires carrying input voltages, how can i make it so that the output voltage equal to the sum of the three input voltages? Please see image below.

2. If there are two wires carrying two input voltages, how can I make it so that the motor turns one way when Vx>Vy then turn the other way when Vy>Vx? Vx and Vy are voltage outputs from a colorimeter. Please see image below.
http://server6.uploadit.org/files/battlestar-motor.jpg


Thank you very much [Linked Image]

Tools for Electricians:
Re: help on basic circuits #128845 02/20/04 09:18 AM
Joined: Aug 2001
Posts: 7,520
P
pauluk Offline
Member
Hi there battlestar, and welcome to ECN.

1. Assuming that we're talking about relatively low-voltages, the typical way that such a task is carried in modern electronics is by using an operational amplifier (frequently called an op-amp). These come in integrated circuit form, and require just the addition of a few components to set up the correct conditions for whatever task is required.

A simple adder circuit is fairly easy to achieve, and in fact was one of the earliest applications of the op-amp in analog computers.

Have a look here for some information about the op-amp and some of its uses:
http://www.phys.ualberta.ca/~gingrich/phys395/notes/node99.html

Check the page Current Summing Amplifier for your specific task.

2. Assuming we're talking about a small DC motor, a bridge circuit can be employed for this task. The exact arrangement will depend very much on the signal levels and power required for the motor, but you might like to explore some of the links here for ideas:
http://www.epanorama.net/links/motorcontrol.html



[This message has been edited by pauluk (edited 02-20-2004).]

Re: help on basic circuits #128846 02/24/04 11:20 PM
Joined: Oct 2000
Posts: 2,721
Scott35 Offline
Broom Pusher and
Member
Battlestar;

Paul has given very good information, and will be of great assistance for the applications you refer to.

I was wondering a few things.
<OL TYPE=1>

[*]Any AC inputs, or AC coupled to DC,


[*]What polarity will the three voltage sources be at any given time,


[*]Will the Motor's input polarity ever change,


[*]What type / level of components are to be used for monitoring / control.
</OL>

For #2 above, will the inputs be "+" or "-" (in respect to ground)? Will any input be the opposite of another input?

Per #3, will the power supply for the Motor be a 3 wire DC type (+ / GND / -), or will the Motor's input be sampled from another source?

Per #4, what level of "Tech" do you need?
May be simple - like with all passive components,
May be more complex - like with Opamps and/or discrete components,
May be really complex - like with interfacing capabilities.

Sounds like fun!

Scott35


Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!

Featured:

2020 National Electrical Code
2020 National Electrical
Code (NEC)

* * * * * * *

2020 Master Electrician Exam Preparation Combos
2020 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
pcsailor
pcsailor
Minneapolis, MN, USA
Posts: 21
Joined: September 2019
Show All Member Profiles 
Top Posters(30 Days)
Trumpy 9
Popular Topics(Views)
271,982 Are you busy
205,870 Re: Forum
193,932 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.3