Search:
Search questions and share your knowledge with the world here on Questionpoint.

:: Categories ::

Interview Question in Integrated Circuit

Interview Question :: Electronics for noobs regarding touch switch

I want to make a touch switch with a 555 IC. I don't want any kits but I do have a schematics already and procedures from this site:

http://home.maine.rr.com/randylinscott/j...

My questions are:
1. It says that the input voltage should be around 5 - 15 volts. What do I need to add to the circuit to step down a 220 volts electric source?

2. How do I make a homemade touch plates?

3. If I were going to attach this to a light source, what should i modify in the schematics for the light to remain on instead of going out after a few seconds?

4. I'm planning to integrate this with an microchip wherein the first touch would activate the light normally, second touch would make it dimmer till it goes out and third would just turn it off. Where should I place the microchip in the schematics?

Answers to "Electronics for noobs regarding touch switch"

RE: Electronics for noobs regarding touch switch?
1. You need some sort of DC supply that delivers 12 volts. One of those small plug in units would do fine. 3. To drive anything that runs off of 220 volts AC you will need a relay, in the spot where the buzzer is now. Set Vcc to 12 volts instead of 5 volts and use a 12 volt relay with contacts that can handle 230 VAC at several amps. Be careful with connections to the 220 line, be sure they conform to all of the wiring codes. Be sure they are not interconnected to the low voltage DC part of the circuit. 4. I don't understand #4. A 555 is a microchip. What is this other microchip you want to add. You seem to have little or no experience with electronics or electricity. You are fooling around with lethal voltages, so be very careful.
Vote for this answer ::

RE: Electronics for noobs regarding touch switch?
My first reaction when I see your first question is that you are out of your league. If you don't understand this step, then you need to learn more about AC and DC electricity. It is important to understand so that you know what is safe and what can be very dangerous. 220 volts will be AC. 220 volts is very dangerous to work with. To step it down to a lower voltage you need a transformer. Then you will need to convert this to DC which requires a rectifier and some capacitors. You could learn a lot with this project, but you need to be sure to learn the basics first.
Vote for this answer ::

RE: Electronics for noobs regarding touch switch?
With most circuitry, isolation is not really an issue as most electronics are nicely tucked away inside a insulated or earthed package. You don't usually come into contact with any of the electrical paths. There is some circuits require you do so, though, and the touch switch is one of them. For this reason, isolation is important. Isolation means you need to be concerned with leakage currents to the mains. For this reason, you need to use a good quality transformer for the power supply. Unfortunately, some of the circuits available on the internet do not take this simple safety step and are basically an accident waiting to happen. A 7805 or a 7815 (or anything in between) should do for a regulator. You will also need a rectifier bridge and a electrolytic capacitor. You can make touch plates using printed circuit board. A 555 is best as an astable oscillator. It can be used as a monostable but there are better monostables available. If you want the light to toggle, you will need a bistable of some sort. The 555 can be made bistable (http://www.eleinmec.com/article.asp?5). You may be able to adapt this circuit. Not sure about your last. Don't be afraid to add circuits. IC's like the 555 are cheap and only need a few resistors etc. to make them function.
Vote for this answer ::

Notify me whenever an answer is posted for this question Update Alert Setting

Advertisement2

Top Tags

- Sharepoint Developer Interview Questions - Java Interview Questions - J2EE Interview Questions - ASP.NET Interview Questions - MOSS 2007 Interview Questions - WPF Interview Questions - Microsoft CRM Interview Questions - Technical Interview Questions for Programmers - SSRS Interview Questions - SSAS Interview Questions

Search questions and share your knowledge with the world here on Questionpoint.

:: Categories ::

Interview Question in Integrated Circuit

Interview Question :: Electronics for noobs regarding touch switch

Top Tags