Fade on, Fade off Interior lights

Master 5 wrote

"Out of curiosity does anyone know a simple RC circuit that would case a light to fade on?"

This was the answer, but it is just not a good way to go about it.

hi,

for a pwm circuit device, this piece may work.  http://www.vellemanusa.com/us/enu/product/view/?id=350605. now to control the input to allow a ramped voltage to trigger it, i'd have to check my notes.

mark

Could someone tell me where they are drawing up the circuits to post here?.. I see cardomain.com logos, but I haven't the time at this moment to go there and look around.

A simple RC circuit to control  an interior light would be one transistor, one resistor, and one capacitor... if someone clues me in on the drawing, I'll draw a picture. Basically the RC circuit feeds the base on the transistor.. the transistor controls the light.

Jim

I myself was kinda thinking something similar with the relays. Now all practicality issues aside this is all for fun and theory, not something I think anyone would actually use.

The reason I didn't bother trying to design the "fade" with an array of standard relays is that I think it would brighten in stages as each relay is energized, not really producing a smooth fade. The other factor is feedback from the relay coils, but I imagine diodes could correct that.

Now as far as transistors it's been a long time since I have messed with any. For the masters test all I needed to know regarding transistors is how to identify a "PNP" vs. "NPN". Easy enough. The main uses I have had for transistors in the past was when I needed to energize a relay coil using a device with too week an output. A resistor/transistor easily accomplishes this.

Other then that I would be interested in learning how using a transistor can accomplish this "fade on" we are talking about. Is there a way anyone (mad scientisits, lol) can explain this. If its too complicated don't bother but I would think it not that difficult.

Thanks

Oh and as far as drawing my circuits I need some help also. I had a bunch of schematic symbols I collected over the years but when I need something different I will do a google search or do it by hand in paint program. usually plain black and whites and it is very limited.

Not very pretty but it works. However I would much prefer a way to have them neat and in color as I see others post. The way I have been doing it is very time consuming as I have to cut and paste each componenet and draw all the lines manually.

Thanks