Transistors Again
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Posts: 46,084
Hello,
While in the middle of solving one problem with the TWS/RWS 434, I
ran into an old problem.
I cannot seem to get a grip on making transistors work effectively
all the time even after reading much documentation. For me they
don't seem to work like what I've read, or I'm just missing something.
Anyhow, my transistor is driving a relay that turns on at 5V. For
some reason the transistor (NPN) switches on regardless of the base.
The good news is that it does not blow up anymore. I tried grounding
the base but it still switches on whether or not the base is
connected or not, or if its logic 1 or not.
I'm using the standard circuit with a diode connecting the coil.
Thanks for any more information that will open my eyes.
DJ
While in the middle of solving one problem with the TWS/RWS 434, I
ran into an old problem.
I cannot seem to get a grip on making transistors work effectively
all the time even after reading much documentation. For me they
don't seem to work like what I've read, or I'm just missing something.
Anyhow, my transistor is driving a relay that turns on at 5V. For
some reason the transistor (NPN) switches on regardless of the base.
The good news is that it does not blow up anymore. I tried grounding
the base but it still switches on whether or not the base is
connected or not, or if its logic 1 or not.
I'm using the standard circuit with a diode connecting the coil.
Thanks for any more information that will open my eyes.
DJ
Comments
1. What type of NPN transistor are you using.
2. Are you 100% sure that you know which pins
are the emitter, collector and base..?
It sounds like you may have it connected wrong.
Bruce
webmaster@r...
http://www.rentron.com
Original Message
From: <ContactMe@S...>
To: <basicstamps@egroups.com>
Sent: Monday, October 23, 2000 4:07 PM
Subject: [noparse][[/noparse]basicstamps] Transistors Again
| Hello,
|
| While in the middle of solving one problem with the TWS/RWS 434, I
| ran into an old problem.
|
| I cannot seem to get a grip on making transistors work effectively
| all the time even after reading much documentation. For me they
| don't seem to work like what I've read, or I'm just missing something.
|
| Anyhow, my transistor is driving a relay that turns on at 5V. For
| some reason the transistor (NPN) switches on regardless of the base.
| The good news is that it does not blow up anymore. I tried grounding
| the base but it still switches on whether or not the base is
| connected or not, or if its logic 1 or not.
|
| I'm using the standard circuit with a diode connecting the coil.
|
| Thanks for any more information that will open my eyes.
|
| DJ
|
|
|
|
|
|
I pretty certain what the pins are. They are also marked on the back
of the transistor.
I put a 470 resistor from emmitter to ground and it shut the
connection off which is what I want. However, now I cannot get it to
switch on from the data0 pin of the RWS434.
It is a 2N3903 transistor from radio shack.
Thanks, DJ
--- In basicstamps@egroups.com, "Bruce" <breyno2@r...> wrote:
> DJ,
>
> 1. What type of NPN transistor are you using.
>
> 2. Are you 100% sure that you know which pins
> are the emitter, collector and base..?
>
> It sounds like you may have it connected wrong.
>
> Bruce
> webmaster@r...
> http://www.rentron.com
>
>
>
Original Message
> From: <ContactMe@S...>
> To: <basicstamps@egroups.com>
> Sent: Monday, October 23, 2000 4:07 PM
> Subject: [noparse][[/noparse]basicstamps] Transistors Again
>
>
> | Hello,
> |
> | While in the middle of solving one problem with the TWS/RWS 434,
I
> | ran into an old problem.
> |
> | I cannot seem to get a grip on making transistors work
effectively
> | all the time even after reading much documentation. For me they
> | don't seem to work like what I've read, or I'm just missing
something.
> |
> | Anyhow, my transistor is driving a relay that turns on at 5V.
For
> | some reason the transistor (NPN) switches on regardless of the
base.
> | The good news is that it does not blow up anymore. I tried
grounding
> | the base but it still switches on whether or not the base is
> | connected or not, or if its logic 1 or not.
> |
> | I'm using the standard circuit with a diode connecting the coil.
> |
> | Thanks for any more information that will open my eyes.
> |
> | DJ
> |
> |
> |
> |
> |
> |
| I pretty certain what the pins are. They are also marked on the back
| of the transistor.
OK.
| I put a 470 resistor from emmitter to ground and it shut the
| connection off which is what I want. However, now I cannot get it to
| switch on from the data0 pin of the RWS434.
Be sure to connect the resistor from the HT-12D D0 pin, to the base
of the transistor. Try a 5-10K for this base resistor.
| It is a 2N3903 transistor from radio shack.
Should work when the D0 pin of the HT-12D goes to logic 1, and turn
off when it's logic 0.
If you still have problems, contact me off-list at the email address below.
I'll go over it with you, and get you going ASAP.
Bruce
webmaster@r...
http://www.rentron.com
| Thanks, DJ
|
|
| --- In basicstamps@egroups.com, "Bruce" <breyno2@r...> wrote:
| > DJ,
| >
| > 1. What type of NPN transistor are you using.
| >
| > 2. Are you 100% sure that you know which pins
| > are the emitter, collector and base..?
| >
| > It sounds like you may have it connected wrong.
| >
| > Bruce
| > webmaster@r...
| > http://www.rentron.com
| >
| >
| >
Original Message
| > From: <ContactMe@S...>
| > To: <basicstamps@egroups.com>
| > Sent: Monday, October 23, 2000 4:07 PM
| > Subject: [noparse][[/noparse]basicstamps] Transistors Again
| >
| >
| > | Hello,
| > |
| > | While in the middle of solving one problem with the TWS/RWS 434,
| I
| > | ran into an old problem.
| > |
| > | I cannot seem to get a grip on making transistors work
| effectively
| > | all the time even after reading much documentation. For me they
| > | don't seem to work like what I've read, or I'm just missing
| something.
| > |
| > | Anyhow, my transistor is driving a relay that turns on at 5V.
| For
| > | some reason the transistor (NPN) switches on regardless of the
| base.
| > | The good news is that it does not blow up anymore. I tried
| grounding
| > | the base but it still switches on whether or not the base is
| > | connected or not, or if its logic 1 or not.
| > |
| > | I'm using the standard circuit with a diode connecting the coil.
| > |
| > | Thanks for any more information that will open my eyes.
| > |
| > | DJ
| > |
| > |
| > |
| > |
| > |
| > |
|
|
|
|
|
(http://www.nutsandvolts.com/stmpindx.htm) and download the article file
"Stamp6.pdf". This article, entitled "Silicon Steroids rpr the
Stamp...". It is is Adobe Acrobat format and will explain how to hook up
transistors to the Stamp. If you have trouble finding the article contact
me off the reflector and I will send the article to you.
Tom Churchill
ContactMe@S... wrote:
> Hello,
>
> While in the middle of solving one problem with the TWS/RWS 434, I
> ran into an old problem.
>
> I cannot seem to get a grip on making transistors work effectively
> all the time even after reading much documentation. For me they
> don't seem to work like what I've read, or I'm just missing something.
>
> Anyhow, my transistor is driving a relay that turns on at 5V. For
> some reason the transistor (NPN) switches on regardless of the base.
> The good news is that it does not blow up anymore. I tried grounding
> the base but it still switches on whether or not the base is
> connected or not, or if its logic 1 or not.
>
> I'm using the standard circuit with a diode connecting the coil.
>
> Thanks for any more information that will open my eyes.
>
> DJ
to my relays at 5v, for 12v relays, use an opamp to raise the voltaje.
CSc> I pretty certain what the pins are. They are also marked on the back
CSc> of the transistor.
CSc> I put a 470 resistor from emmitter to ground and it shut the
CSc> connection off which is what I want. However, now I cannot get it to
CSc> switch on from the data0 pin of the RWS434.
CSc> It is a 2N3903 transistor from radio shack.
C