# Transistors Help - SK100/SL100

S

#### Steve

Jan 1, 1970
0
I need the SK100 and SL100 transistors to build the following circuit:
http://www.electronic-circuits-diagrams.com/motorimages/3.gif

The problem is I cant find where to buy those. I look at RadioShack,
they didnt have it. I looked through the DigiKey and Jameco catalog and
they dont have it either..

What are some transistors that are equivalent to and can replace SK100
and SL100 and still make this circuit operational?

Thank you

J

#### Joerg

Jan 1, 1970
0
Hi Steve,

Just look for transistors with similar data (voltage, current, beta).
The voltage here is low so that shouldn't be critical. Depending on the
motor check out whether BC337 and BC327 might do it. If you draw several
hundred mA you might want to look for some others that could be mounted
on a heatsink.

Regards, Joerg

C

#### CFoley1064

Jan 1, 1970
0
Subject: Transistors Help - SK100/SL100
From: "Steve" [email protected]
Date: 10/26/2004 6:40 PM Central Daylight Time
Message-id: <[email protected]>

I need the SK100 and SL100 transistors to build the following circuit:
http://www.electronic-circuits-diagrams.com/motorimages/3.gif

The problem is I cant find where to buy those. I look at RadioShack,
they didnt have it. I looked through the DigiKey and Jameco catalog and
they dont have it either..

What are some transistors that are equivalent to and can replace SK100
and SL100 and still make this circuit operational?

Thank you

Hi, Steve. The requirements of the circuit are NPN and PNP power transistors
that can switch 1 amp and have a Vceo of greater than 10V or so. Basically,
just about any NPN and PNP TO-220 transistors will do. If you want to do Radio
Shack, try the

J

#### Joerg

Jan 1, 1970
0
Hello,
Hi, Steve. The requirements of the circuit are NPN and PNP power transistors
that can switch 1 amp and have a Vceo of greater than 10V or so. Basically,
just about any NPN and PNP TO-220 transistors will do. If you want to do Radio
Shack, try the
And make sure they have enough beta. Those 1K resistors won't source
more than about 8mA of base current.

Regards, Joerg

B

#### Brian

Jan 1, 1970
0
Steve said:
I need the SK100 and SL100 transistors to build the following circuit:
http://www.electronic-circuits-diagrams.com/motorimages/3.gif

The problem is I cant find where to buy those. I look at RadioShack,
they didnt have it. I looked through the DigiKey and Jameco catalog and
they dont have it either..

What are some transistors that are equivalent to and can replace SK100
and SL100 and still make this circuit operational?

Thank you

I went to Mouser and put in SK100 (in their search box) and it came up
with a lot of replacement transistors (which they have in stock). Their Web
site is: http://www.mouser.com/
Brian

S

#### Steve

Jan 1, 1970
0
CFoley1064 said:
Hi, Steve. The requirements of the circuit are NPN and PNP power transistors
that can switch 1 amp and have a Vceo of greater than 10V or so. Basically,
just about any NPN and PNP TO-220 transistors will do. If you want to do Radio
Shack, try the

Hello,
Can you repeat the last part of your message, all I see is "If you want
to do Radio Shack, try the" What should I try?

Thank you

S

#### Steve

Jan 1, 1970
0
Joerg said:
Hello,

And make sure they have enough beta. Those 1K resistors won't source
more than about 8mA of base current.

Regards, Joerg

Good point. Someone else also told me the same thing saying that the 1K
base resistors only allow 9mA of base current and that is not enough to
get the SL and SK100 saturated with 1A load.

How can that problem be resolved? Do you have any suggestions?

Also it was pointed out that there is no base current limiting between
the transistors. Would adding two 1K resistors in series between Q3 &
Q4 and Q6 & Q5 fix that problem? Would the resistors be placed like
this (orientation of transistors is incorrect in that image, just
wanted to illustrate the resistors):
http://users3.ev1.net/~srudenko/img/motorckt2.gif

Thanks

J

#### James Meyer

Jan 1, 1970
0
I need the SK100 and SL100 transistors to build the following circuit:
http://www.electronic-circuits-diagrams.com/motorimages/3.gif

The problem is I cant find where to buy those. I look at RadioShack,
they didnt have it. I looked through the DigiKey and Jameco catalog and
they dont have it either..

What are some transistors that are equivalent to and can replace SK100
and SL100 and still make this circuit operational?

Thank you

The SK100 is really a 2SK100. They were originally Japanese transistor
numbers. They always had "2" as the first number so you will very often see
people drop the 2 and just use the rest of the number.

Of course, the US standard, 2Nxxxx, always started with 2 but you never
see those contracted. Don't know why.

Jim

J

#### Jim Meyer

Jan 1, 1970
0
Steve said:
I need the SK100 and SL100 transistors to build the following circuit:
http://www.electronic-circuits-diagrams.com/motorimages/3.gif

The problem is I cant find where to buy those. I look at RadioShack,
they didnt have it. I looked through the DigiKey and Jameco catalog and
they dont have it either..

What are some transistors that are equivalent to and can replace SK100
and SL100 and still make this circuit operational?

Thank you

I posted a message about Japanese transistors this morning before
I woke up. Please ignore it.

The SK and SL100 transistors are crap and only rated to 0.5 amps.
If you substitute better transistors into the original circuit you
will distroy them because of the lack of base current limiting
resistors in the upper two transistors.

Here is a web site for a much better motor driver (H-bridge).

http://www.armory.com/~rstevew/Public/Motors/H-Bridges/Blanchard/h-bridge.htm

Jim

S

#### Steve

Jan 1, 1970
0
Jim said:
"Steve" <[email protected]> wrote in message
I posted a message about Japanese transistors this morning before
I woke up. Please ignore it.

The SK and SL100 transistors are crap and only rated to 0.5 amps.
If you substitute better transistors into the original circuit you
will distroy them because of the lack of base current limiting
resistors in the upper two transistors.

Here is a web site for a much better motor driver (H-bridge).

http://www.armory.com/~rstevew/Public/Motors/H-Bridges/Blanchard/h-bridge.htm

Jim

Hi,
We fixed the current limiting problem by adding two 1K resistors
between the bases of the transistors as seen here:
http://forum.webzila.com/index.php?act=Attach&type=post&id=2441

We are also planning to use TIP115 instead of SK100 and TIP110 instead
of SL100

Is the other circuit still a better choice? We already have a 9V DC
motor and I see that the circuit you showed takes in 12V. Would our
current motor still work?

Thanks for the help

J

#### Joerg

Jan 1, 1970
0
Hi Steve,
Good point. Someone else also told me the same thing saying that the 1K
base resistors only allow 9mA of base current and that is not enough to
get the SL and SK100 saturated with 1A load.

How can that problem be resolved? Do you have any suggestions?
You could either:

*Lower the value of the 1K resistors
*Use Darlington transistor on the motor bridge
*Use n-channel and p-channel FETs instead.

FETs sometimes come with enough reverse diode protection which allows
you to get rid of the four diodes but you have to consult the data
sheet. ON-Semi, IR and lots of others offer suitable FETs.
Also it was pointed out that there is no base current limiting between
the transistors. Would adding two 1K resistors in series between Q3 &
Q4 and Q6 & Q5 fix that problem? Would the resistors be placed like
this (orientation of transistors is incorrect in that image, just
wanted to illustrate the resistors):
http://users3.ev1.net/~srudenko/img/motorckt2.gif
Yes, you are right that this circuit diagram appears to be
'sub-optimal'. Relying on a limited beta of the input pair is not a good
idea. And no, the four resistors in the motor path won't fix it. The
motor can't run through 1K resistors and it wouldn't prevent the top
transistors from frying. You need a resistor in series with each bridge
driver line. With FETs this problem goes away because they don't have a
gate DC current unless you drive the gate voltage past the data sheet
limits.

BTW, you can buy complete motor driver bridges for a couple Dollars or
so. Many of these have the diodes and the whole enchilada right on the chip.

Regards, Joerg

J

#### James Meyer

Jan 1, 1970
0
Hi,
We fixed the current limiting problem by adding two 1K resistors
between the bases of the transistors as seen here:
http://forum.webzila.com/index.php?act=Attach&type=post&id=2441

We are also planning to use TIP115 instead of SK100 and TIP110 instead
of SL100

Is the other circuit still a better choice? We already have a 9V DC
motor and I see that the circuit you showed takes in 12V. Would our
current motor still work?

Thanks for the help

The TIPXXX transistors are darlington transistors and as is pointed out
in the referenced web site, darlingtons waste power. The situation will be
worse at 9 volts than it would be at 12 volts. On the other hand, the circuit
with MOS-FETs should work as well at 9 volts as it does at 12 volts. I still
recommend the MOS-FET version.

Jim

B

#### Brian

Jan 1, 1970
0
Steve said:
http://www.armory.com/~rstevew/Public/Motors/H-Bridges/Blanchard/h-bridge.htm

Hi,
We fixed the current limiting problem by adding two 1K resistors
between the bases of the transistors as seen here:
http://forum.webzila.com/index.php?act=Attach&type=post&id=2441

We are also planning to use TIP115 instead of SK100 and TIP110 instead
of SL100

Is the other circuit still a better choice? We already have a 9V DC
motor and I see that the circuit you showed takes in 12V. Would our
current motor still work?

Thanks for the help

You can replace Q4 and Q6 with "NDP6020P" power P-channel MOSFET's and Q3
and Q5 with a "NDP4060L" power N-channel MOSFET's (and even take out the two
base resistors you added) and the circuit will work very well. You can get
the NDP6020P at Mouser for $1.39 and the NDP4060L for$1.06. I use them in
switching regulators and I am sure they would do very well in your
application.
Brian

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