change on / off switch – modulate peed of on off by using?

Hi Everyone,
I am a novice of novices. I'd be grateful for anyone who can shed light on this:

1. I would like to replace a manual on off switch with something like a pot that can control the frequency in which on and off collectively occurs, from fractions of a second to a full second.

2. Is this type of thing off the shelf or must it be custom developed?

3. If Custom, any recommendations on where to get it done?

Thank you all for sharing your expertise with me!

What sort of circuit is the switch controlling, voltage and current? Does the duty cycle of the off and on have to be 50:50, that is a square wave. Do you need a linear control, or logarithmic, where one end of the span of the pot has a much finer control of the frequency compared to the other end.
Does the thing run continuously, or is it intermittent.
The simplest way of generating the timing would be a 555 timer, which is an analogue solution using an RC network, where the R is variable. A microcontroller could be used if you feel the need to write some software, and it potentially may offer a more versatile solution. The pot could be on an ADC on the micro which would control an internal timer.
Depending on the load that the switch has to supply, you may need a relay of some sort. The on and off times of many power translation devices, be they solid state or a relay are not symmetrical, so some tweaking may be needed if you want an equal duty cycle.
There may be commercial solutions, there are all sorts of DIN rail devices these days, not aware of anything specific though, you would need to contact suppliers of DIN rail modules and describe your need.
Without knowing more best I can offer,
cheers,
Richard

Hi Everyone,
I am a novice of novices. I’d be grateful for anyone who can shed light on this:

Hello. I am also interested in this question!

The type of control depends on the load being switched. Since you want to switch on for only fractions of a second a relay is probably not a good choice. So you need some kind of electronic switching element. For low-current and low-voltage DC loads you can use a 555 timer. There are MANY circuits on the Web that will show that application. For higher current or voltage you can use a MOSFET or IGBT as the swtiching element controlled by the 555.

You can also use a microcontroller such as an Arduino connected to a power switching circuit. There are also many of these circuits posted on the Web. Many are DIY and don't require custom PCBs or anything.

If you want a commercially developed product you can look at PLC type modules. These are industrial-grade products which are robust, supported and well tested for a variety of loads. The cost will be higher but you can do basically anything with the modules within a given family.

While it's true that electromechanical relays may not work, opto mos relays are capable of good switching speeds, typically less than a few mSec, at the expense of more modest power handling. Again, without knowing what the characteristics of the system are, it is hard to say precisely what is needed. Since the original poster has not replied, one must assume that a solution has been found, or interest has been lost,
cheers,
Richard

Richard, Chris. Thank you for taking time to share your experience and knowledge. I am looking into these ideas. Very appreciated!

The type of control depends on the load being switched. Since you want to switch on for only fractions of a second a relay is probably not a good choice.

Richard, thank you for your input- very much grateful.
You asked the following and I'll tell you what I know:

(1) What sort of circuit is the switch controlling, voltage and current?
Driving Voltage: 28-49 VAC
Power consumption: 3 to 5w / M^2

At this point it is 2 batteries with an on/ off switch going to glass to polarize the glass.


Does the duty cycle of the off and on have to be 50:50, that is a square wave. Do you need a linear control, or logarithmic, where one end of the span of the pot has a much finer control of the frequency compared to the other end.

Wow, I never thought to ask myself this, but in short linear would be fine.

Does the thing run continuously, or is it intermittent.
It runs continuously as long as it is on.