RZ2G5 relay.. not enough current, solution plz.

[sonaiko]

I bought the RZ2G5 relay that works on 5v. i dont know how much current it needs and i didnt find its datasheet anywer!! I connected that to my parallel port that gives out 4.5v but it refuses to work! eventhough it works with a 4.5 normal DC voltage from a transformer. the reason is PC parallel port doesnt give enough current!!

what should i do to solve this problem? i want the parallel port to control the relay.

thanx.

 

[williB]

One way to do it requires some extra circuitry,
you need to latch the data comming from the parallel port ,
then you need to use a transistor to handle the current needed to drive your relay..

 

[sonaiko]

One way to do it requires some extra circuitry,
you need to latch the data comming from the parallel port ,
then you need to use a transistor to handle the current needed to drive your relay..

how can i do that? details plz?

 

[williB]

find me a timing diagram of the parallel port..
while i look up the chips required..

 

[williB]

SPP - standard parallel port..
Pin 1 of the parallel port is the strobe , this is an active low signal (TTL)
that tells you when data is available ( to be sent to your relay)..
If you use a 74LS374 then you must use an Inverter between the clock (pin 11) and the strobe line..
then just send your data to the parallel port and the 374 will latch the data

Data is first applied on the Parallel Port pins 2 to 7. The host then checks to see if the printer is busy. i.e. the busy line should be low. The program then asserts the strobe, waits a minimum of 1uS, and then de-asserts the strobe. Data is normally read by the printer/peripheral on the rising edge of the strobe. The printer will indicate that it is busy processing data via the Busy line. Once the printer has accepted data, it will acknowledge the byte by a negative pulse about 5uS on the nAck line.
**broken link removed**

 

[sonaiko]

SPP - standard parallel port..
Pin 1 of the parallel port is the strobe , this is an active low signal (TTL)
that tells you when data is available ( to be sent to your relay)..
If you use a 74LS374 then you must use an Inverter between the clock (pin 11) and the strobe line..
then just send your data to the parallel port and the 374 will latch the data

Data is first applied on the Parallel Port pins 2 to 7. The host then checks to see if the printer is busy. i.e. the busy line should be low. The program then asserts the strobe, waits a minimum of 1uS, and then de-asserts the strobe. Data is normally read by the printer/peripheral on the rising edge of the strobe. The printer will indicate that it is busy processing data via the Busy line. Once the printer has accepted data, it will acknowledge the byte by a negative pulse about 5uS on the nAck line.
**broken link removed**

im sorry, but all that i know. what does this have to do with raising the current input to the relay?

 

[Nigel Goodwin]

im sorry, but all that i know. what does this have to do with raising the current input to the relay?

Nothing that I can see?.

Try looking at the 'Hardware Extras' section of my PIC tutorials, I give a simple circuit for feeding a relay from a PIC pin - you can use the same circuit from a parallel port.

 

[williB]

i was trying to show you that you can not just hook up a relay to the parallel port.
but i have outlined all the info that you will need to do so..
once you get the 374 hooked up you will need a transistor to drive your relay..
sometimes i wonder why i bother.. :roll:

 

[Nigel Goodwin]

i was trying to show you that you can not just hook up a relay to the parallel port.
but i have outlined all the info that you will need to do so..
once you get the 374 hooked up you will need a transistor to drive your relay..
sometimes i wonder why i bother.. :roll:

I was wondering as well!, don't you think it was rather complicated?, and for no purpose?.

You only need a resistor from the port pin to the base of a transistor, and a relay fed from that (as in my PIC circuit I mentioned), what's the 374 for?.