Author Topic: Toggle switches alternative  (Read 331 times)

POTL

Toggle switches alternative
« on: February 07, 2021, 05:25:57 AM »
Hello.
want to know if there are replacements for the classic toggle switches?
I am thinking about using a microcontroller to supply voltage and a tact switch (for example, this one https://www.taydaelectronics.com/electromechanical/switches-key-pad/tact-switch/tact-switch-6-3-6-6mm-3- 1mm-smd-spst-no.html) to switch the operating mode of the microcontroller.
What control elements can be selected (transistors, CMOS, e.t.c.) there are requirements for them 1) Minimum capacitance or lack thereof like conventional switches 2) Minimum or no resistance like conventional switches 3) Modes of operation SPST (one or more channels) SPDT (one or more channels). are there such elements in nature?

ElectricDruid

Re: Toggle switches alternative
« Reply #1 on: February 07, 2021, 06:33:37 AM »
If you use the tact switch connected to an IO pin to toggle the uP's state, then you have the full variety of CMOS switches available. These days we're well past just the 4016/66, 4053, and 4051. There are literally hundreds, in all combinations (quad SPST, SPDT,4:1, 8:1, dual 8:1, you name it), and in all package sizes and voltages too. The trouble is often finding one!
Yes, these switches have some On resistance, but not much; 10s or 100s ohms at worst. Often it is lower at higher supply voltages. Capacitance and charge injection is another question, but not something I've read much about, so I can't help with that.

I've used the DG-series switches sometimes, for example. These are nice for Synth work since they support a +/-15V supply for the analog side, but have level shifters so they can be controlled with 5V logic.

https://www.vishay.com/analog-switches/tab/products/
https://www.renesas.com/eu/en/products/analog-products/switches-multiplexers

There are even ones designed for audio that wait for a zero-crossing in the signal before they switch to reduce clicks!


POTL

Re: Toggle switches alternative
« Reply #2 on: February 21, 2021, 08:31:48 AM »
thank 4016 and similar devices are outdated?

ElectricDruid

Re: Toggle switches alternative
« Reply #3 on: February 21, 2021, 11:00:24 AM »
I'm not sure that "outdated" is the word I'd use. They're "old", certainly, having been around since the 1970s! It's rather that there are a lot of other options these days, and the 40xx series chips aren't the best for every situation.

They're still available, still cheap, and still do the job, so sure, use them if they suit the application. For certain things, they're a nuisance, since they only cope with a 15V power supply, which often means you need to set up a 7.5V bias level just for them, and then have everything going to the switch chip with DC-blocking caps both in and out. That's annoying. Plus the switch signals have to be full voltage - you can't switch the switches with 5V logic. Of course, if you're controlling it with 4000-series logic too, no problem. So it depends on the situation.

r080

Re: Toggle switches alternative
« Reply #4 on: February 22, 2021, 02:50:05 PM »
If it is something the user would not change often, I wouldn't rule out DIP switches.