6532 interfacing question for the electronic experts

[Kande Laber]

Hello,

In discussion "https://groups.google.com/g/pal6502/c/fgn8odHnCGo" I documented that Liu's I/O gadget LEDs draw around 7 mA from 2nd RIOT (6532) port B.

Now, I am planning to directly hook up my old "Kosmos CP4" relais interface to port B (see attached pictures including diagramms)..

As the transistor stage is linked with a 1 Kiloohm resistor to the computer output port, I would figure that each of the 8 channels would draw at most 5 mA.

The 6532 datasheet says "typicial 5 mA".

Question question for the electronic experts:

Is it safe to do that?

If not, how else would you connect it?

Best regards

[Hans Otten]

That will work. A PIA Port can drive that transistor. 

 Be aware that relays will generate lots of electronic noise. The diode over the relay will help but the preferred way is via optocouplers. 
Since the relays will switch low voltage and reasonable currents it will be allright. Above 20V is to be avoided!

[Kande Laber]

Thanks a lot for your advice.
The relays will switch approx 9V DC to drive motors, a magnet and lamps from my old Fischertechnik kits.

Similar to that shown in enclosed picture.

Best regards