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CD4066 questions?

With the split 9v supply the cd4066 won't work?
Data sheet says INPUTS -.5v TO Vdd + .5v
what will lowering the supply voltage do?
If I understand you correctly I need a lower supply voltage to the CD4066?
If so wouldn't a simple diode in the Vdd of the CD 4066 cause a voltage drop?
Other better switches for this application?
will simulate removing C32
Thanks
 
revamped circuit

Removed C32 but added a 1K resistor to ground from 10K pot so the input to U1a won't get grounded directly (???)
sweep diagrams look same w or w/o C32
Just waiting on concensus of the CD4066 see previous posts
 
dang it forgot pic

here is pic of revamp
 

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  • revamp2.GIF
    revamp2.GIF
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With the split 9v supply the cd4066 won't work?
Data sheet says INPUTS -.5v TO Vdd + .5v
what will lowering the supply voltage do?
If I understand you correctly I need a lower supply voltage to the CD4066?
If so wouldn't a simple diode in the Vdd of the CD 4066 cause a voltage drop?
The input to the CD4066 is from -8V to +8V.
Its power supply voltages must include these voltages. Use -9V and +9V to power it.
A CD4066 made by Texas Instruments has a max allowed total supply of 20V.
The control pin must swing from -9V when it is off to +9V when it is on.

A resistor is missing at the output of the top filter opamp that is the equivalent to R13 on the second filter.
 
Final hopfully finished design?

pdf of schematics.
R13 missing??
there are 3 pages of display but only posted one.
any suggestions as I want to maybe get his project going
 

Attachments

  • inputsrevamp.pdf
    46.2 KB · Views: 171
  • psrevamp.pdf
    23.8 KB · Views: 197
  • left channelrevamp.pdf
    42.6 KB · Views: 169
  • right channelrevamp.pdf
    46.1 KB · Views: 155
  • display1revamp.pdf
    61.7 KB · Views: 206
Hi Mr. DEB,
The CD4066 has inputs that swing from -8V to +8V so its negative power supply and for the control input and for the indicator LED must be -9v, not 0V.
The LM3916 ICs will cause noise on the +9V power supply voltage when they switch between no current to about 1.25A so add a 100uF capacitor to the supply pins of each LM3916 to smooth the voltage.

Hi Blue Bill,
The LM3916 has a max allowed dissipation of 1.365W. I didn't calculate the max adjustable current for each LED but if they are 25mA and all 10 are turned on then the dissipation in the LM3916 is (9V-2V) x (25mA x 10)= 1.75W which is too high. The 15 ohm resistor will dissipate 0.94W and reduce the dissipation of the IC.
 
If I understand correctly?

Instead of going to ground with the control pins to OPEN the switch I need to connect to the -9 supply?
Will add the 100uf to the supply pins.
 
The CD4066 needs to have a -9V and a +9V supply.
Its is turned off when its control pin at -9V and it is turned on when its control pin is at +9V. The indicator LED also needs to connect to -9V and its resistor value doubled.
 
Vellman circuit

In the Vellman EQ circuit they use the CD4066 but the supply is only + and grd.
Being how the circuit I am doing has a split supply is why I need to split the supply to the CD4066's?
just curious
 
I also can't remember the Velleman kit because it was 100 threads ago.

The CD4066 and most other Cmos ICs have a max allowed input signal level that is within their supply voltage range. Your signals go from -8V to +8V so the supply voltage for your CD4066 must be at least -8V and +8V (the datasheet allows 0.5V more input).

Your schematics are confusing because the supplies are -12V and +12V on one page but -9V and +9V on another page. I think you are using only -9V and +9V for everything.
 
yes 9 v supply

I went through and changed the supply voltages as well as add caps etc as per suggestions.
Also had to renumber the op amps as I removed a couple.
hopfully I have everything right??
In the Vellman EQ spectrum circuit it has several CD4066's with one supply voltage.
I have a link somewhere to the entire circuit.
Any suggestions on laying out the supply lines to prevent ground loops, osscilating etc.
I am just getting started on pcb layout.
It was suggestedto put 100uf cafs on the supply of the lm3916's
will 10uf caps work or just buy some tatanium caps?
 
You can buy good quality electrolytic capacitors that are in the same small case for a 10uF/16V and for a 100uF/16V. There is a very small difference in cost.

I have had many tantalum capacitors fail so I don't use them any more.
 
I had already purchased

the 10uf non polarized caps before you suggested going with the 220nf caps.
though I could use the 10's instead of purchasing more.
 
the 10uf non polarized caps before you suggested going with the 220nf caps.
though I could use the 10's instead of purchasing more.
I don't see 10uF non-polarized caps in your latest schematics.
 
They were/are the 10uf/220nf caps

I posted a schematic that HAD 10uf caps on the inputs to the op amps.
it was suggested to change to 220nf to allow a larger frequency spectrum to enter the circuit.
I changed to 220nf, order from Mouser the 220's.
Had already ordered the non polarized from ALL Electronics surplus
All Electronics | Electronic and Electro-Mechanical Parts and Supplies at Discount Prices
pretty good prices on alot of stuff.
In process of laying out board. need to look at how I am going to do the power traces seeing how I am going to have 4 seperate boards (power, main filter board, display board, back-lighting board.)
on the main boardwill have 10 conductor ribbon cables to connect the LED display board to the main board (lm3916's)
been contemplating different ideas etc.
just woried about ground loops, osscilating etc.
trying to do single sides boards as the Pulsar kit has real thin boards that its easy to etch through the traces (if I figure out how to apply the green transfer stuff then it should work better (the green kinda adds a waterproffing to the ink to prevent pitting of the traces.
 
Using same op amp for L & R channels

Am I just being over worried about using same op am for the left and right channels for my input mixer for an EQ unit?
Using 1 TL074 op amp for inputing the right and left channels.
Worried about crosstalk or ??
Tryingto layout a pc board and contemplating using same op amp for both channels (may lay out better with out jumper wires or long traces.
 
You might be able to hear 40dB of crosstalk between channels when one channel ihas a signal and the other channel is silent.
But opamps have crosstalk that is 1000 times better. Don't worry about using one IC for both channels.
 
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