Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

pull up resistor?????

Status
Not open for further replies.
Z

zelsenussi

Junior Member level 1
Joined
Jun 28, 2008
Messages
19
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,400
i have optical sensor(infra red ) sensor ,and i gave it vcc and ground and when i am testing its output i found it that vout=2.5v (detect) and (vout=0) (no detect)
but i need (vout=5v)when(detect) and (vout=0)when (no detect)..
one of my friend made something i didnt understand what did he do? but he used only one resistor ??and when i asked him he tald me Pull up pull down resistor?????????
how does this resistor afect in this way???
 

Here a example for a pull-up resistor, I'm assuming that the sesor output is build with a phototransistor or photodarlington, output is connected to Vcc trough a pull-up resistor and the emitter is to 0V.

What type of sensor are you using now?

Bye
Powermos
 

most of sensors and digital ICs have open collector configuration and hence their output voltage doesnt reach the supply... in those cases a pull up resistor is needed which is nothing but a resistor to the supply... this supplies current to the output from the supply effectively reducing the load offered to the output pin...
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top