how to increase current in parallel port ?

[ajaykumar988]

how to amplify parallel port current

The port gives off eough voltage (the relay is rated at 5v, port output pins give of 5.something). The relay does not work; i dont think there is eough current.

Is it possible for me to tie multiple output pins together in some way to make the current higher while maintaining the same voltage level?

Would the parallel port itself have some sort of diode on the output pins so that electricity doesnt flow back into the circuit?

 

[Ramesh_maharjan]

parallel port relay 2n2222

you should try using current amplifier

first isolate the parallel port with outside circuit for protection, then amplify the current of the signal either using opamp transisor or driving IC etc........

 

[IanP]

parallel port relays latch

The parallel port pins can not drive much .. the can probably source <3mA and sink <25mA (typical currents for the 74374 output latch) ..
You will need to "amplify" the ouput "voltage" signal by using external transistors ..
Here is one example:

                             Vcc
                              |
                              +------+
                              |    __|__
                            Relay   /^\  Diode 1N4002
                             Coil  /---\
                              |      |
                              +------+
                              |
                           | / 
                 4.7K    B |/  C
parallel port >-\/\/\/\/---|        NPN Transistor: BC547A or 2N2222A
data pi                    |\  E
                           | V
                             |
parallel port >--------------+
ground pin                   |
                          Ground

Regards,
IanP

 

[budhy]

parallel port increase

More simple and realiable if you use ULN2003

 

[kishorekhatri]

increase parallel port output

u can use optocoupler b/w the parallal port pin and relay, to get enogh cuurent to run relay.
search for optocoupler

 

[Hero]

increasing current in parallel

Hi,

Use solid state relay based on photovoltaic element or integrated solid state relay. Look at IR site for details.

If you don't need galvanic isolation use approprated MOSFET as switch.

 

[siongboon]

Any transistor interface would be able to drive the relay.
You can try a signal transistor (low current capacity) BC549.

Circuit reference to interface digital logic (0V 5V) to a mechnical relay.
**broken link removed**

 

[yogi]

see the source and sink current of parallel port. 2mA/24mA. So it won't be able to drive a relay. If you connect relay directly to parallel port then ur port will burn. Use some transistor with it. See the link below
**broken link removed**
**broken link removed**

Bibin John
www.bibinjohn.tk