Roger Dewhurst said:
They are only to interface between 4026 chips and 7 element LEDs. I
thought
that perhaps the ULN2003 is a little over the top for that job. I have
found other ones but they are all Darlingtons. I could use single
transitors but that mean much more wiring and soldering.
R
Try digital transistors, also known as biased transistors provided your
max. current is less than 100mA. They save you mounting the resistors.
They come in TO92, SOT323 and SC75.
See On Semiconductor MUN5211T1 as example of bais resistor transistors.
On
www.onsemiconductor.com Go to Bipolar Transistors > Bias Resistor
Transistors
on the main page.
also see Fairchild FJN3114R as exampel of biased transistors.
On
www.fairchildsemi.com go to 'small signal transistor' tab on main page
and then select 'digital' tab in the left hand column under the 'Function'
section.
They come in NPN and PNP nominal 50V 100mA with different bias resistors
Some of the range are available from
www.mouser.com in small quanteties.
You can also try low threshold small signal FETs, but they tend to be more
expensive.
Gerhard van den Berg
CSIR