CD4066 use

[moe_3_moe]

Hello,

I am trying to control the first switches of the CD4066(Quad) to control four different resistive circuits. To do so, i want to use 2-to-4 decoder to generate four different possible possibilities connected to the 4 different switches. I want to ask if this is right?

Thank you.

 

[ericgibbs]

Hello,

I am trying to control the first switches of the CD4066(Quad) to control four different resistive circuits. To do so, i want to use 2-to-4 decoder to generate four different possible possibilities connected to the 4 different switches. I want to ask if this is right?

Thank you.

hi,
That should work OK.
Which 2 to 4 decoder IC are you using.???

 

[moe_3_moe]

I still didn't decide, but i have one at home (74) family. do you have any other recommendations? I am still confused when it comes to the connection of each switch. I am thinking about connecting the output of the decoder tot he input of the switch and get the output to the resistive circuit but the problem is the control feature for each switch which i am not sure about its function.

 

[ericgibbs]

I still didn't decide, but i have one at home (74) family. do you have any other recommendations? I am still confused when it comes to the connection of each switch. I am thinking about connecting the output of the decoder tot he input of the switch and get the output to the resistive circuit but the problem is the control feature for each switch which i am not sure about its function.

hi,
Look at this simple sketch.
It would be best if you used a CMOS 2 to 4 decoder IC.

EDIT:

 

[moe_3_moe]

hi,
Look at this simple sketch.
It would be best if you used a CMOS 2 to 4 decoder IC.

EDIT:

Oh, Thank you. What should go into pin 1? I am thinking it should be connected to Pin13? and 2 will be working if the switch is closed?

 

[ericgibbs]

Oh, Thank you. What should go into pin 1? I am thinking it should be connected to Pin13? and 2 will be working if the switch is closed?

hi,
Its not that way..
Image that each on of the blocks is a switch,, say 1 and 2 are the switch contacts and 13 is the lever/toggle by which you operate the switch.

Instead of the operating lever that you would have on a switch, the switch is voltage controlled.

When pin 13 is high , say 5V then the switch is closed and when pin 13 is low 0V, then the switch is open.

There are four these switches in the IC, all separate switches.... OK.????

 

[moe_3_moe]

I got it now. Great. I appreciate your help and time.

Thank you

 

[crutschow]

If you are using this to switch resistive circuits, be sure to allow for the "on" resistance of the 4066. It varies with both the supply voltage and the signal voltage.

 

[moe_3_moe]

If you are using this to switch resistive circuits, be sure to allow for the "on" resistance of the 4066. It varies with both the supply voltage and the signal voltage.

Actually it makes a difference for my project. I am trying to swith between four resistors connected to a transistor , so i can establish 4 different base currents Ib. I am looking in the datasheet for something that leads for internal Resistance for the CD4066 but i think there is a formula that involves signal voltage and supply voltage , right?

 

[crutschow]

The "ON Resistances, Ron" in the "Electrical Characteristics" table contains the values you are looking for.

 

[Boncuk]

Hi,

if the On-resistance is an issue I suggest to use NXP-semiconductor's 74LVC1G66.

It has an On-resistance of 6Ω at 5V other than the 4066 which has an On-resistance of 125Ω.

The chip is manufactured as single channel switch in TSSOP5 and SC-74A packages.

Here is the data sheet.

Boncuk