SV: RE: [sdiy] Power supply mystery....

[Karl Ekdahl]

Funny thing... connected a 4050 to power without any
connections, yeilds 38mA usage. With all inputs
connected to +5v i've got 60mA. Is this really how it
should be or am i using a *really* old 4050
(4050BPC)??

Karl


--- Fredrik Carlqvist <Fredrik.Carlqvist at iar.se>
skrev:

>  
> The ADC0804 outputs are TTL compatible, they can
> source about 6mA each.
> When all the outputs are shorted to ground, they
> will draw 48mA at
> least. You should have resistors on the outputs
> before swamping them to
> ground. 
> 
> Try to set the bit depth control to '8'
> (disconnected, and see if your
> PS can handle that... 
> 
> 
> Fredrik C
> 
> 
> 
> > -----Original Message-----
> > From: owner-synth-diy at dropmix.xs4all.nl 
> > [mailto:owner-synth-diy at dropmix.xs4all.nl] On
> Behalf Of Karl Ekdahl
> > Sent: den 1 september 2005 13:22
> > To: synth-diy at dropmix.xs4all.nl
> > Subject: [sdiy] Power supply mystery....
> > 
> > Hi list, i'm currently trying to update my old
> > bitcrusher but has run into some weird problems. 
> > 
> > I was going to build a tiny zener dual supply for
> it
> > but it seems the circuit draws too much power (the
> > voltage drops) allthough my readings says 30mA.
> While
> > connecting a 1A 7x05-based supply the voltage
> instead
> > *rises* to about 10V. The supply drops to +-5v
> again
> > if disconnecting the 0804 and the 4050. My guess
> is
> > that it, again, has something with too much (or
> too
> > little) power to do. 
> > 
> > I guess this circuit should draw <100mA but since
> i
> > don't really know how to calculate the whole thing
> i'm
> > not sure.
> > 
> > I'm totally stuck on this, if anyone feels like in
> a
> > good mood, please take a look at the schematic
> > (http://www.cocospalme.se/niema/bitcrusher2.jpg),
> it
> > is all but impossible i've done something really
> > wrong...
> > 
> > thanks
> > 
> > Karl
> > 
> 
>