I have a project on doing simple dual slope ADC using only our lab kit component.But the problem is I can't not come up with any ideas to make switch from V in and Vref controlled by my kits which is included only basic transistors 2en3904,JFET,and some IC like 7474,7485,LM324,counter LS191,BCD display.The switch should be controlled by the clock.
Does anyone have something interesting about dual slope please help me
here is diagram that what professor asking me to follow

 

So, to be clear, you are asking how one can switch between Vin and Vref using only the components listed, correct?

 

So, to be clear, you are asking how one can switch between Vin and Vref using only the components listed, correct?

yeah,right.i know that using manual switch is impossible to operate a dual slope adc but i can't think of any solutions to make a switch between vin and vref and it has to be controlled by a clock.there must be something that my limited knowledge can't reach.
I have to build the switch to zero out the integrator either.

 

The JFET likely could be used as a switch. What is its part number?

 

The JFET likely could be used as a switch. What is its part number?

its MF102
i think about it but i think it can'tcontrol the time switching between two stage

 

Any one who has any suggestion of any kind of component is okay.I'll figure it out I try to do on my own.

 

I'd say you should look into transmission gates.... you can configure your transistors as an analog multiplexer...