[sdiy] TDA 4070 chip??

[soundgood at web.de]

soundgood at web.de schrieb am 12.01.02:
> I thought so to and tried to replace one with a CMOS 4070 but it is not used as a normal gate in the circuit.
> The power pins are the same but pins 2 to 6 and 9 to 13 have squarewave inputs which get drawn down by a gate voltage around 5V and than the Vdd actually has this squarewave superimposed on it (or the mix of some squarewaves if more gatesignals are present.
> 
> Lets try to explain that again.
> 
> There are ten gate inputs and ten squarewave ninputs to the circuit of which this chip is a part. (Th rest are only transistors.
> 
> The squarewaves are applied to the chip and the gate signals are added to the squarewavs and only than does the circuit produce any outpt.
> 
> This output is actually the modulation of the power supply voltage.
> 
> And I don't think that a CMOS chip draws enough current to modulate the power supply.
> 
> As long as the CD4070 I tried was not broken it diffently doesn't work.
> 
> Hope that makes some sense.
> 
> T
> 
> > It's probably a CD4070 quad EXOR gate.
> 


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