Greetings everyone. I have a weird idea and not sure if this concept is plausible at all. Typical bistable multivibrator takes input from momentary switch and turns it into latching output. Is there a circuit for the opposite task? Take latching switch with two possible outputs (e.g. 0V and 5V) and every time it is switched from one state to another there is a short-term (~10 milliseconds) appearance of 5V on the output of some circuit. Having some examples of such circuits would be great.

 

Greetings everyone. I have a weird idea and not sure if this concept is plausible at all. Typical bistable multivibrator takes input from momentary switch and turns it into latching output. Is there a circuit for the opposite task? Take latching switch with two possible outputs (e.g. 0V and 5V) and every time it is switched from one state to another there is a short-term (~10 milliseconds) appearance of 5V on the output of some circuit. Having some examples of such circuits would be great.

There are a number of ways to do this.

A simple way is to use an XOR gate (being sure to take into account any voltage level differences) and send your latch output to both XOR input, but send one of them directly and the other through a low-pass RC filter with an appropriate time constant. When the switch as been in the same state for a long time, both inputs to the XOR will be the same and the output will be LO. When the switch changes state, the direct path will change immediately but the other one will stay at the old value for 10 ms, resulting in a HI output during that time.

 

Wbahn’s suggestion is an excellent one.
If you require a clean, exact pulse width, follow the XOR output with a non-retriggerable monostable.

 

The Circuit may depend on what You are ultimately trying to accomplish.
What does your project do ?
.
.
.

 

A simple way is to use an XOR gate

Not sure if this would be a problem in the real circuit, but it's possible that the XOR gate could generate a short burst of high-frequency oscillations as the RC voltage slowly goes through its threshold voltage.

This possibility can be eliminated by using a Schmitt-trigger quad NOR package to generate the XOR function (example below):

 

If you are conversant in microcontrollers, it is a simple task using interrupt on change.

 

Not sure if this would be a problem in the real circuit, but it's possible that the XOR gate could generate a short burst of high-frequency oscillations as the RC voltage slowly goes through its threshold voltage.

This possibility can be eliminated by using a Schmitt-trigger quad NOR package to generate the XOR function (example below):
View attachment 293357

The XOR gate circuit works on 74HC, but I have not tried it on all possible logic families - some may oscillate.
If the input is directly from a switch, then it needs to be debounced first.

 

Greetings everyone. I have a weird idea and not sure if this concept is plausible at all. Typical bistable multivibrator takes input from momentary switch and turns it into latching output. Is there a circuit for the opposite task? Take latching switch with two possible outputs (e.g. 0V and 5V) and every time it is switched from one state to another there is a short-term (~10 milliseconds) appearance of 5V on the output of some circuit. Having some examples of such circuits would be great.

Actually there is a simple scheme to provide exactly that, and it is called a MONOSTABLE multivibrator. Usually available as an IC with true and complementary outputs.
The CD4098 is one example.

 

Actually there is a simple scheme to provide exactly that, and it is called a MONOSTABLE multivibrator. Usually available as an IC with true and complementary outputs.
The CD4098 is one example.

I'm not sure it's so easy to make a 4098 trigger on both rising and falling edges of the input signal.

 

Actually there is a simple scheme to provide exactly that,

That's not simpler than the XOR circuit if you want a pulse on both the rising and falling edges of the input signal.

 

It does have inputs for both rising edge trigger and falling edge trigger. And it is interchangable with the MC14528 and MC14538. One big advantage is that the pulse width has a clearly defined formula and is not dependent on device properties.The very worst case would be having to use both sides and OR the outputs.
You will need to studythe application chart in the manual because there is a lot of functionality available.