Anything related to transistor arrays, i.e. small-scale integrated circuits containing a limited number (usually 8÷16) of well matched transistors. They are used for applications where component matching is paramount or to simplify the layout of a design where many transistors must be used in ...
0
votes
3answers
106 views
Can I somehow use one PWM output to set various LEDs to different brightness?
I would like to build a project in which 15 groups of LEDs are set to a brightness level. I have an Arduino with digital PWM outputs (which can mimic a range of voltages.) How can I do this?
One ...
3
votes
1answer
128 views
Why my solenoid valves open only if power is turned on at last?
I have a set of eight 48Vcc solenoid valves that I'm controlling using an Arduino. The open and close signals are sent using the Arduino's SPI lines, which are connected to a circuit composed by a ...
0
votes
0answers
180 views
Constant current source array IC to use together with HT1632c LED driver chip
There's this HT1632 LED driver chip I want to build a LED screen driver circuit with and I want the LEDs to be bright so I cannot power the LEDs directly from the IC and need a current source for each ...
1
vote
2answers
162 views
What it is the maximum “real” current by the collector that can be drawn from ULN2067B
I am building a 5-volt-to-24-volt DC converter using ULN2067B. According to the datasheet this device can support 1.5 A per darlington per collector.
Does that mean that all the darlingtons can ...
0
votes
1answer
192 views
BJT pre-biased arrays slower than discrete?
I've got a circuit that works - it's job is to convert a TTL square wave into a +/- 12 volt square wave.
simulate this circuit – Schematic created using CircuitLab
Note that the ...
2
votes
1answer
256 views
Questions about a simple LED circuit using the ULN2003A
I'm a newbie, and am trying to drive several independent LEDs using a transistor array in a 5-volt CMOS circuit. Here's what I've come up with, showing only the first LED:
In the schematic, ...
4
votes
1answer
444 views
Why might the collector-emitter voltage for this transistor be so high?
I'm attempting to use an NPN transistor as a switch, to drive an LED load. So I am only interested in the off and saturated states.
My understanding is that when the base-emitter junction is ...
1
vote
1answer
165 views
Unable to keep 2nd shift register in chain of 3 from “leaking”
I am working on a word clock, and I am using 3 shift regsiters (CD4094BE) and 3 darlington transistor arrays (ULN2003A) to control whether or not 21 different words are on or off. The words consist of ...
1
vote
1answer
247 views
Custom device with multiple gates tied together in Eagle
I'm trying to create a transistor array device in a small library I'm working on in Eagle. The device has five P-Channel MOSFETs. The source of each MOSFET is internally tied together and connected to ...
3
votes
3answers
1k views
Any IC similar to ULN2003A with latch or enable/disable?
I'm working on a project that uses a ULN2003A (darlington transistor array) and I need to enable/disable it. The point is that ULN2003A does not have enable/disable pin.
I think that a IC with latch ...
-3
votes
1answer
215 views
Fet array operation [closed]
Can anyone explain to me the operation of the following FET arrray .
http://www.diodes.com/datasheets/DMN2019UTS.pdf
2
votes
2answers
2k views
What IC is good for driving an array of smaller solenoids?
I have a 7 segment display where all segments are driven with a solenoid. In order to switch each segment I have to pulse a short current on the solenoid. To change the segment I have to pulse it in ...
2
votes
3answers
761 views
Darlington Array IC that can sink 1.5A
I am looking for a darlington array IC like the ULN2803a that can sink up to 1.5A. It needs to be in a DIP. Any recommendations? Its needed because i am driving a stepper motor and requires 1.2A per ...
4
votes
1answer
583 views
Why do 0v have to be connected when using two power supplies and ULN2803A?
The other day I was playing with a ULN2803a and a stepper motor. I spent ages trying to work out why it wasn't working and why i was reading ~14V as an output on the PIC I was using. So why did I ...
