I would use a Schmitt Trigger.

You can make one either from an Op Amp (or Voltage comparitor) or use a CMOS Hex Schmitt Inverter such as the 40106.

I suggest that you post the circuit of the Op Amp one that you are not happy with so we can analyse it and suggest imprevements.

What was the issue that you were not happy with?

Didn't you look at the datasheets for the 555, the 741 and the LM358?

The output low of an ordinary 555 is +0.1V when its load current is low. Its output high is +3.6V.

Many 741 opamps don't work if their supply voltage is less than 10V.
If you found a 741 that works with only 5V then its output low is +1.2V and its output high is +3.8V wothout load current.

The LM358 works when its supply is as low as 3V.
With a 5V supply its output low is 0V or +1.0V depending on its load current.
Its output high is +3.8V without load current.

You need a Schmitt trigger or a circuit with hysteresis to switch quickly when it gets dark.

About 45 years ago I made Schmitt trigger circuits with 2 transistors. Look in Google. Cmos Schmitt trigger inputs on inverters and gates are used now.

If you want it to operate on 5 Volt, there are at least 3 solutions.

1. use a 74HC14 Hex Schmitt Trigger IC. This has enough current source and sink capability to drive a LED. This solution requires the least number of components. But don't neglect to connect the unused inputs to gnd.

2. Use a Voltage Comparitor IC such as the LM311 configured as a Schmitt Trigger. It has a transistor output that will drive the LED, see the data sheet for details.

3. Use an Op Amp that can operate from a single 5V supply and use an N channel MOSFET (such as the 2N7000) to drive the LED.

Options 3 & 3 have the advantage that you can set the hystersis according to your need. Whereas, in the case of option 1, the hystersis is set inside the IC.

Originally Posted by Suraj143

What about making a Schmitt trigger by using 555 like in the attachment.

What I need is to add the LDR & transistor circuit to this circuit to give 5V or 0V in the output.

There is a Schmitt Trigger inside the 555. But the problem is that the hystersis is set inside the 555 to about one third of Vcc. This is probably too wide for your situation.

Originally Posted by Suraj143

I need to operate from 5V.

When I use an op amp when in ambient light the output led goes dim not giving 5V or 0V. I used a hysteresis too but still the problem is there.

Without looking at the Op Amp's data sheet, I suspect that the Op Amp does not switch to a low enough voltage to switch the transistor off. That's why I suggested you use an N channel MOSFET in a previous post.
Here is the circuit i replaced LM358 instead of 741.
http://www.uoguelph.ca/~antoon/circ/sensor2.htm

There is no hystersis in this circuit. You need a resistor from the output of the Op Amp to the + input. But it won't operate at 5 Volt.

But this 555 circuit the led wont dim its giving 5V or 0V.

I don't understand your last sentence. It does not make sense.

Originally Posted by Suraj143

Hi ijcox thanks for your suggestions. I like your first method.

The 74HC14 Hex Schmitt Trigger IC.
What about the input side? I need only a V/R & LDR is that right? Yes

& the output I can connect to a led via resister? Yes
Thanks

However, as I said in my original post, the hystersis may be too wide since it is set inside the IC.

You could possibly solve this by applying some negative feed back.

This would require another Schmitt Trigger (you have 5 spares in the IC) with its input connected to the output of the first one. Connect a resistor from the output of the second to the input of the first. I have not done the calculations, but I expect that this will reduce the hystersis.

EDIT

I made an error in the above.

You don't need a second Schmitt, just connect the feedback resistor from the output of the first to its input. set the value of the resistor to give the hystersis that you need.

Note the edit to the previous.

Originally Posted by Suraj143

Hi ijcox when I’m testing the LM358 I added hysteresis to the wrong pin.

I replaced the Rh (feedback resister) to the output pin & to the (-) inverting pin which is connected to the LDR.

I’ll give a try to place that resister to the out & non inverting pin.

But the original circuit gives that to the inverting pin.

Hystersis requires positive feedback. So the feedback resistor must go from the output to the + input.