http://www.electricalbasicprojects.com/electronics-mini-projects-using-opamp/

 

Are you looking for a critique?

 

Are you looking for a critique?

I am not able to understand where to connect switch in relay. I.e to which terminal of relay

 

I am not able to understand where to connect switch in relay. I.e to which terminal of relay

What are you trying to do? Be as specific as possible.

The circuit you linked to was created by a total newbie; if you tell us what you are trying to do, we can likely come up with something much simpler...

 

What are you trying to do? Be as specific as possible.

The circuit you linked to was created by a total newbie; if you tell us what you are trying to do, we can likely come up with something much simpler...

The concept is when I push the button then relay should be energised and even when I release push button it should glow led for few seconds depending on rc time constant

 

I am not able to understand where to connect switch in relay. I.e to which terminal of relay

That is not your fault. This is one of the worst project descriptions I've ever seen. There are ten statements under "Circuit Operation", and eight of them are wrong. The schematic has critical errors, missing parts, and just generally makes no sense. There are dozens of people on this forum who will gladly help you design a better circuit. It will take less time than explaining all of the things wrong with the one you have.

SO - what is it you want a circuit to do?

ak

 

I have no idea why they used a relay to switch that simple circuit?
Why the P.B. was not used directly is a mystery!
Appears a very poor design to achieve what they say.
Max.

 

That is not your fault. This is one of the worst project descriptions I've ever seen. There are ten statements under "Circuit Operation", and eight of them are wrong. The schematic has critical errors, missing parts, and just generally makes no sense. There are dozens of people on this forum who will gladly help you design a better circuit. It will take less time than explaining all of the things wrong with the one you have.

SO - what is it you want a circuit to do?

ak

I want to design a circuit which works on that concept...

 

I want to design a circuit which works on that concept...

Do you want to design a circuit...or...do you want a circuit designed to do your concept?
Battery + capacitor + 3 resistors + PB switch + LED + N-channel MOSFET. Circuit will have the LED fade out, or add a relay for sharp cutoff.

Ken

 

I want a ckt to work for

Do you want to design a circuit...or...do you want a circuit designed to do your concept?
Battery + capacitor + 3 resistors + PB switch + LED + N-channel MOSFET. Circuit will have the LED fade out, or add a relay for sharp cutoff.

Ken[/QUOT

Do you want to design a circuit...or...do you want a circuit designed to do your concept?
Battery + capacitor + 3 resistors + PB switch + LED + N-channel MOSFET. Circuit will have the LED fade out, or add a relay for sharp cutoff.

Ken

I want a ckt to work for my concept

 

I want to design a circuit which works on that concept...

Unfortunately there is no "concept" to follow here as the circuit cannot work, period. Even assuming the box labeled "push button" has a power source to turn on the relay the lamp will just turn on and off with the same push button, there is no delay.

A simpler circuit to do the very same action is just the 9V battery, the push button, and the lamp. The rest is just junk that has no function.

So, we ask again: what do you want the circuit to do? Is that turn on with the button, then turn off after some delay?

The more detail you tell us the better we can assist you.

 

Unfortunately there is no "concept" to follow here as the circuit cannot work, period. Even assuming the box labeled "push button" has a power source to turn on the relay the lamp will just turn on and off with the same push button, there is no delay.

A simpler circuit to do the very same action is just the 9V battery, the push button, and the lamp. The rest is just junk that has no function.

So, we ask again: what do you want the circuit to do? Is that turn on with the button, then turn off after some delay?

The more detail you tell us the better we can assist you.

Ya my concept us to turn on with push button and off after some delay after I release the push button

 

The time-off delay is set by R1 and C1.

Ken

 

What is the power source for your light?
What is the power source for your timer?
What light or how much light so you want to control. Ken's circuits show a single LED, but with the relay you can control a larger light source.

ak