Will this circuit work?

[smpaladin]

http://www.geocities.com/smpaladin/circuit1.gif

This is what the above circuit is supposed to accomplish: As long as
a magnet is held above the hall sensor, it will turn on the coil. It
does that by utilizing a power transistor.

Will this setup work properly? Will it work properly if up to ten of
these circuits are connected to eachother and how much battery power
would I need to run it?

 

[John Fields]

On 26 Sep 2004 06:44:40 -0700, smpaladin@yahoo.com (smpaladin) wrote:

http://www.geocities.com/smpaladin/circuit1.gif

This is what the above circuit is supposed to accomplish: As long as
a magnet is held above the hall sensor, it will turn on the coil. It
does that by utilizing a power transistor.

Will this setup work properly? Will it work properly if up to ten of
these circuits are connected to eachother and how much battery power
would I need to run it?

---
I won't run properly unless you connect the coil between the collector
of the transistor and battery + and connect a diode across the coil
with the cathode of the diode going to battery + and connect the
emitter of the transistor to battery -. It also won't work properly
if you don't have enough current coming out of the Hall sensor, and
you may toast the transistor if you don't put a resistor between the
output of the Hall sensor and the base of the transistor.

As for the rest of it, until you can more clearly describe what the
parts look like, electrically, and what you really want to do, you're
just pissing in the wind.

--
John Fields

 

[CFoley1064]

Subject: Will this circuit work?
From: smpaladin@yahoo.com (smpaladin)
Date: 9/26/2004 8:44 AM Central Daylight Time
Message-id: <6753235c.0409260544.6bb30078@posting.google.com

http://www.geocities.com/smpaladin/circuit1.gif

This is what the above circuit is supposed to accomplish: As long as
a magnet is held above the hall sensor, it will turn on the coil. It
does that by utilizing a power transistor.

Will this setup work properly? Will it work properly if up to ten of
these circuits are connected to eachother and how much battery power
would I need to run it?

Hi, Paladin. There are many types of Hall Effect sensors, and you're not too
specific about which one you're using, so I can't say for sure. However...

Many hall effect sensors are made with "open collector" output. That means
that, when they're on, their output pin will sink a few mA of current from a
pullup resistor or other source.

If you've got a type like that, you might want to try using a PNP transistor
and try something like this (view in fixed font or M$ Notepad):

.----------o--------------o----.
| | | |
| | | |
| | | |
| | .-. |
| .----o---. R| | |
| | + | | | |
| | | '-' |
| | Hall | ___ | |<
| | Effect o----|___|-o--|
--- | Sensor | R |\
- | | |
| | | .---o
| | - | | |
| '----o---' | |
| | | C|
| | - C|
| | ^ C|
| | | |
'----------o---------------o---'
created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

Choose R such that about 1/10th of the current required by the relay coil will
be drawn by the base (note that many of these hall effect sensors are limited
to about -20 mA output current, so keep that in mind).

I hope this works for you. Be sure to check your sensor to check the specs.
If you're not sure, feel free to post again with more information. Battery
voltage, relay coil resistance, sensor type would all be helpful.

Good luck
Chris

 

[Bullwinkle Jones]

John Fields wrote:

On 26 Sep 2004 06:44:40 -0700, smpaladin@yahoo.com (smpaladin) wrote:

As for the rest of it, until you can more clearly describe what the
parts look like, electrically, and what you really want to do, you're
just pissing in the wind.

"It's all coming back to me now", said the blind man as he peed into the
wind..

--