Design a circuit that utilizes an SCR and and an LDR, along with the necessary components, to reverse the rotation of a DC motor when a shadow is detected. What i meant is cant*

 

Welcome to AAC!
Is this a school/college assignment?

 

Welcome to AAC!
Is this a school/college assignment?

college assignment

 

Please post your best effort at doing this assignment, so that guidance can be given where necessary. We do not do assignments for you.

 

well i have one

 

the problem is i need the ldr to be 0 ohms and ldr cant be 0 ohms its so impossible and also were not allowed to used relay so were having a hard time to get it.

 

Also in a practical circuit sense, there could be an issue of using immediate reversal ?
A use of a simple comparator could be used to ensure off when at a shadow is detected.

 

reverse the rotation of a DC motor

Why are you showing AC to power the DC motor?

 

SCR is an rectifier

 

yup were limit on using components on this assignent this is the closer i can get i also think this only works in simulation not in practical real experiment

 

the problem is i need the ldr to be 0 ohms

Why?

 

yup were limit on using components on this assignent this is the closer i can get i also think this only works in simulation not in practical real experiment

In the real world, it is not always practical or safe in regards to such as motor-mechanism's etc, to do an instant motor reversal,
In practice, either a small delay is used to allow the motor to stop before reversing, or a ramp up at start can be used .

 

SCR is an rectifier

So half-wave rectified is ok for the motor?

 

DC motor should be fine with DC, regardless if the DC is steady or pulsed. if that was not the case PWM would not work to control motor speed.

i have no idea what the transistors in the circuit are meant to do and hope TS can elaborate. for now i removed them and annotated parts so one can have a discussion.
TS thinks that SCR is a rectifier... and rectifiers pass current in one direction. so what is the point in having both SCR1 and SCR2 connected in same directions - if working as rectifiers and triggered by LDR, both will pass current in the same direction.

then what is the reason for D1 since it is in same direction as SCR1?
and what is the reason for D2 since it is wired in opposite direction of SCR2?

 

DC motor should be fine with DC, regardless if the DC is steady or pulsed.

Perhaps not if it's half-wave.

 

Design a circuit that utilizes an SCR and and an LDR, along with the necessary components, to reverse the rotation of a DC motor when a shadow is detected. What i meant is cant*

What are the "necessary components" allowed to be?

Break the problem down into smaller pieces. Forget the motor for now. Can you make a circuit that produces a low voltage when there's a shadow and a high voltage when there isn't (or the other way around)?

 

Perhaps not if it's half-wave.

Not sure i follow... What does the waveform shape has to do with it? I don't see why a DC motor would work even if supplied by AC that has sufficient DC bias... Now you gonna make me test it.

 

in order for the dc motor to counter clockwise bro

 

were allowed to use transistors now im thinking about using h bridge

 

What does the waveform shape has to do with it?

Not the waveshape, the frequency.
The motor may not work well with half-wave pulses at 50-60Hz.