Switches controlled by Microcontroller

[conanhaha]

Hi all~
Want to ask that,
I want to construct a tester circuit with various configuration values, such as different resistor values, I need many switches to close and open to change the resistor values.
This need to be controlled by a micro-controller.
What kind of switches that can be controlled by micro-controller which micro-controller can send signal to close/open the switches to change all the connecting resistors value?

 

[Nigel Goodwin]

Try relays and driver transistors - only relays give perfect switching without any constraints.

 

[conanhaha]

Sorry that I am new to this switching and can't understand well.
What relay should I use and how I should connect them?

I had upload a sample switching that i wish to have.
When 1st test, I wish to connect to R1, R4, R7.
When 2nd test, I wish to connect to R2, R5, R8.
When 3rd test, I wish to connect to R3, R6, R9.

How do I implement this kind switching with micro-controller?

All need to be controlled by micro-controller.
Is that possible i use only 3 switch that can on the example>
(R1, R4, R7),
(R2, R5, R8),
(R3, R6, R9)
each at the same time?

 

[Nigel Goodwin]

By using double pole single throw (DPST) relays you can use one relay for each resistor, but by uisng double pole double throw (DPDT) you can reduce the number of relays required. In either case, you could use any resistor at any time, it's just the programming that is slightly different.

A relay is just a mechanical switch, moved by a solenoid, it's not really an 'electronic' component.

 

[Brevor]

Since you are using the resistors to control the gain of an op amp a 4066 analog switch IC would be a better choice. You would need 3 of them. They are also way cheaper than relays.

 

[Nigel Goodwin]

Since you are using the resistors to control the gain of an op amp a 4066 analog switch IC would be a better choice. You would need 3 of them. They are also way cheaper than relays.

Cheaper, but no where near as good - though they would be fine for the higher values. Relays have the advantage of being completely isolated, and of the lowest possible resistance.

 

[conanhaha]

Thanks again for reply~
Is that any reed relay that build in an IC that make a few reed relay together to save the space?
I think I need quite a number of reed relay
Is that the DPDT or 4PDT consider function as a few relay?