Wiardgroup

I'm sure if I could remember anything from circuits 101, I wouldn't 
have to ask, but since I DON'T...

What's the current requirement for the GR-1209B joystick? 

I'm planning for future expansion of my Blacet/Wiard modular, and I 
want to figure out if my PS500 will power 3 fracracks of modules or 
not. It's going to be close. I'm sure the joysticks don't draw much, 
and I've got 4 of the Mult/Attenuators, which don't draw anything. 

I need a new rack case, and I'm not sure which size to get. I'm 
thinking that if I can get a 9-space rack's worth of modules powered 
off 1 PS500, then I could expand beyond that with a 2nd PS and rack.

Thanks,

Mike FUn

hi Mike,
   this is probably best answered by prof. Richter himself but i measured my Joystick's current draw after i saw your post.
Here's the story:
My Joystick is a GR-1209..... NO "B" ...it is from the original (now discontinued) 1200 series so i can't guarantee that my circuit is EXACTLY identical to yours but i do know that Grant just used single transistor buffers on each vector. i tested it with the x & y vectors controlling the 'bank' and 'envelope' of an original 1200-series miniwave. In all states my meter showed that the draw was BELOW 1ma! (and my meter is not very reliable in the micro-amp range) This is hardly scientific or authoritative but it does indicate that the current draw of the Wiard joysticks themselves is: 'damn small'
I think it bears mentioning that a transistor buffer's current draw is going to vary with the input impedance of the controlled device.
best,
-doc

> What's the current requirement for the GR-1209B joystick? 
> 

At a 10 volt output, each axis draws about 4 milliamps. With the 
gate button pressed the LED draws about 9 milliamps.

So maximum current draw will be when both axis are outputing 
10 volts and the gate button is pressed 4+4+9=17 milliamps.

I call it 25 ma for budgetary purposes, as currents could change 
at temperature extremes.

BTW, as a general engineering rule, you should not load a 
power supply to 100% of it's rated capacity. It will almost certainly 
misbehave at some point, due to overheating. Around 80% is all 
I would try to push any supply for reliable operation over 
temperature range.