soft switch

[timelessbeing]

I have a 12V source, three loads (LEDs), and a common return. I would like to control it with a momentary micro switch, similar to this soft switch circuit: https://www.google.com/patents/US7781920?printsec=drawing
Only I need it to toggle fouir states:
1. off
2. turn on load 1
3. turn on load 1 + 2
4. turn on load 1 + 2 +3

I have seen this type of behaviour in LED headlamps, where you push a button to advance through modes/brightnesses.

Is it possible to create this circuit using common components (transistors, resistors, capacitors etc.)?

 

[Menticol]

You can start with a 4017 decade counter. It's not a discrete component as you wanted, but the site includes some pictures to guide you.

https://sensorsweep.tripod.com/sequencer.html

EDIT: That guy should fix the font size, for god sake!

 

[Reloadron]

I believe this thread is along the lines of what you are looking to accomplish. However, it does not use discreet components.

Is it possible to create this circuit using common components (transistors, resistors, capacitors etc.)?

Yes, it was done that way years ago. For example since the CD4017 counter chip was mentioned if you look at the 4017 data sheet you will note on page 3-52 what the chip consist of. Now for example note the D Flip Flop boxes in the drawing. Each D FF shown can be built with discreet components. This is an example of a D FF built using transistors. So with a small mountain of discreet components you can do as you seem to want to do. Rather than a few Integrated Circuits you just end up with a very high parts count. Much as such circuits were designed 40 or 50 years ago. If you would like to go back even further there is the vacuum tube option also.

Ron

 

[alec_t]

There's talk above about discrete components, but the OP specified common components. So I think common ICs are fair game. That being the case a 4017-based circuit (as mentioned) meets the spec, or it could be done with a 4013 dual latch as per the attached. In this circuit the first latch (U1a) not only toggles but also provides (via R2/C2) switch debouncing.

 

[crutschow]

The minimum component count might be using a CD4015 shift-register, which would require no additional logic gates (although it may require buffer driver transistors for the LEDs if he wants more than a couple mA).

You would just tie the SR DATA serial input to a logic high and use the (debounced) microswitch output to clock the SR. That way each LED will light in sequence and stay lit for each clock pulse. You could tie the fourth output to the RESET input to turn off all the LEDs at the fourth clock pulse.

The CD4015 has two 4-bit registers so you could do as many as 8 LEDs (7 if you wanted the 8th pulse to reset everything).