Questions tagged [sinking]

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0
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2answers
48 views

How to read this figure (UDN2981 max current)?

This question is related to this question: why-are-the-pins-of-an-udn2981-related? In the UDN2981 datasheet, the figure below shows the maximum current (page 14, bottom left picture). Does this ...
0
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1answer
56 views

LED ULN2803 thermal / heatsink questions

I'm intending to use LEDs of 5mm, which have a max forward current rate at 30 mA, or a value of 100 mA, with 10% 1 kHz duty cycle, in a circuit like the one below except some changes: STM32F103C8T6 ...
0
votes
3answers
121 views

Choosing pulldown resistor for 74LS86

I am trying to build a half adder using a 74LS86 XOR gate. Initially I connected both input pins that I am using (9 & 10) on the 74LS86 to the ground rail using 10K ohm resistors. I then connected ...
1
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2answers
2k views

Matching sensor output with PLC input

I am trying to add a height captor for a line of my production where I work. I found this Banner captor (QS30LLPQ) and it has 2 bipolar discrete outputs (PNP and NPN). Now, I am trying to decide which ...
3
votes
2answers
115 views

LED circuit stopped working when expanded

I built a small prototype as shown in my diagram with the Si926 n-FET, 250 ohm pull up resistor. In my prototype board I have only 4 channels connected (only two shown). Only one LED is ever turned on ...
1
vote
1answer
107 views

Rotary Encoder - Power Source for small Fork Light Barriers with NI 9401 [closed]

Task In order to measure the angle and calculate the angular velocity and acceleration of a large metal wheel with a rotational frequency \$f = 0.01 \ldots 1.00~Hz\$, I try to build a custom rotary ...
0
votes
1answer
142 views

LED switch with externally controlled current from sinking output

My device has sinking output (Vcc=3.3V), the LED current (and voltage) is controlled by another device (a voltage controlled constant current source) as indicated at VLED. The LED IV curves (as ...
0
votes
4answers
903 views

Oops! N-channel Mosfet on sinking output

I have designed a simple circuit to drive LEDs using a MAX6964 I2C LED driver/GPO chip. Unfortunately, I somehow missed missed that the outputs are open-drain current-sinking outputs. This is not ...
0
votes
1answer
469 views

Is it possible to sink and source from one output pin using a darlington driver

Sinking and sourcing with a darlington driver I asked a question about sinking and sourcing LEDs while using a darlington driver. The images were slightly unclear so i have redrawn it. I had too many ...
-5
votes
2answers
337 views

How to increase microntroller pin Source and Sink Capacity

I'm working on a project but I've hit a block now. I need to drive a total of 169 LEDs using 26 pins at worst case all may be ON at once. I'm afraid that this may fry the MCU since 200mA is absolute ...
1
vote
1answer
158 views

Led must be mounted SINK or SOURCE so as not to interfere with communications? [closed]

I used 3.3v microcontroller. I want to add TX LED and RX LED communication on RS232, RS485, TTL/CMOS. My question: Led communication must be mounted as SINKING or SOURCING on I/O microcontroller ...
10
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7answers
40k views

Sinking and sourcing current

I have been reading that NPN transistors are sinking and PNP are sourcing devices. I do not really understand this concept. It says current source device connects load to Vcc and current sinking ...
4
votes
2answers
3k views

Driving Relay Board with Shift Register (Shift vs Sink)

I am trying to drive some ebay bought 8 channel relay boards. They are pretty simple, have a launchpad or arduino toggle a pin and the board turns on. However, I need to use a shift register with ...
8
votes
2answers
1k views

How to redesign a circuit to use a current sinking IC rather than a current sourcing IC

I'm building a serial servo controller to learn about electronics and assembly language as part of my hexapod robot project. Quite early on I decided that I needed more I/O channels than my ATTiny2313 ...
19
votes
5answers
10k views

current sourcing, current sinking

I'm a student studying electronics and I'm having trouble understanding the concept behind current sourcing and current sinking. We've covered it in a lab using a 7404 and an LED and all that. Just ...