Thank you for this this is flawless no doubt but i would appreciate if you can create a circuit with same effects using common transistors.

If you're satisfied with your original circuit, other than the fact that it doesn't latch, add a PNP transistor to make it latch.

A discrete SCR has some disadvantages (e.g. base emitter junctions not sized to conduct large currents), but there are some advantages (e.g. base terminals can be used to turn the SCR off). In this configuration, the device is more appropriately called a silicon controlled switch, sensitive gate switch, or sensitive gate SCR.

The current shown in the simulation isn't an issue for 2N2222/2N2907.

 

I think you are being unreasonable expecting crutschow to spend the time redesigning the solution he has provided just to save you from having to buy a CD4093. It will only take you a few minutes to order the CD4093 but it will probably take a few hours to re design the circuit to use only transistors.

Les.

 

There are 4 gates in a single package. Not bad for $0.13 cents per gate or $0.50 per one part.

http://www.ti.com/lit/ds/symlink/cd4093b.pdf

Cost? Try something else to bean count.

 

If $0.50 is too expensive, you can buy from eBay at 5 chips for $0.99 or 10 chips for $1.48 if it was for hobby purposes.

 

Thank you for this this is flawless no doubt but i would appreciate if you can create a circuit with same effects using common transistors.

Nope, I've done the best I can. I don't redesign circuits for arbitrary reasons.
The rest is up to you or someone else, if they so choose.

 

No need to redesign i am happy and thank you for the design you provided i have learned so much here,

 

@crutschow 's circuit needs an extra component and you have to FIX an invisible one.

The extra components is a 0.1 uF usually, ceramic capacitor close to the power pins of the CD4093B IC. These are known as bypass capacitors.

The "invisible" part is that only 3 out of the 4 gates are used. For these types of parts, inputs HAVE to be connected. Generally to ground or Vcc.
The parts will oscillate and burn up if they are not. You can accidentally power the devices from their inputs.

Part of the design process is "Layout", so you can swap input pins on these gates and change which of the 3 devices on the chip your going to use. You could decide to use two of quad devices and two chips. You want to make the layout easier.

DIP packaged devices are falling out of favor. To "future-proof" the design, you might decide to use an SMT packaged device attached to a DIP adapter. www.pro-vantage.com will assemble a digikey p/n on a breakout board for you. Machined pins are used for sockets. Square pins for breadboards.

 

No need to redesign i am happy and thank you for the design you provided i have learned so much here,

If you're satisfied with your original circuit, other than the fact that it doesn't latch, add a PNP transistor to make it latch.

 

The extra components is a 0.1 uF usually, ceramic capacitor close to the power pins of the CD4093B IC. These are known as bypass capacitors.

4000 CMOS circuits are relatively slow and there's only one IC in this simple circuit so lack of the capacitor is unlikely to cause a problem.
Wouldn't hurt to add it though.

The "invisible" part is that only 3 out of the 4 gates are used. For these types of parts, inputs HAVE to be connected. Generally to ground or Vcc.

I'm aware of that.
In my original circuit in post #11, there is a note to that effect.
In my last circuit in post #19 I used all 4 gates.

 

I'm aware of that.

You GURU. The OP/TS, I think needs a greater level of understanding. The bypass cap necessity may depend on all sorts of stuff.

You can't argue that It's not good practice.

An IC bumps the difficulty up a "little". Happy Thanksgiving! Me. Cooking Turkey for mom and me. Mom can only help a "tiny bit". She's confined to bed.