I want to make a normally closed time open delay relay using 555 timer. I want a time delay of about 2 seconds. Please post with proper circuit diagram as I am not so familiar with electronics as I am a mechanical engineer. Thank you.

 

What is the voltage and current of the load for this delay circuit.
Will the 555 be driving a mechanical relay?

 

What is the voltage and current of the load for this delay circuit.
Will the 555 be driving a mechanical relay?

Load will be a DC motor - 9 volt, 1A. I don't know what relay it is. I am posting picture of it. It have 5 pins.

 

Depending on how you want to trigger it.. Make the 47K resistor on pin7 a 22k pot, with a 1k in series ..




There are several designs.....

 

Depending on how you want to trigger it.. Make the 47K resistor on pin7 a 22k pot, with a 1k in series ..


View attachment 126917

There are several designs.....

Actually the motor will run continuously and after a dealt of 2 second relay should triggered and open the circuit so that motor will not run until main power supply is off. Timer will reset when main PS is off.

But how to calculate time delay? Can you provide the detailed circuit? I also don't know how to wire relay. Help is highly appreciated. Thank you

 

Calculator here, its the resistor and capacitor on pins 6,7


http://www.csgnetwork.com/ne555timer1calc.html

 

Calculator here, its the resistor and capacitor on pins 6,7


http://www.csgnetwork.com/ne555timer1calc.html

Means changing 100uf capacitor and 2K resistor can vary the delay time right? But then what is the role of 22K pot Mr. Dodgydave is saying about?

 

what is the role of 22K pot

Adjustability. You can dial in the exact time you want the delay to be.

Quick question for you: You want the motor to run for (oh, lets say) 2 seconds then shut down until power is recycled? Or do you want the motor NOT to run for 2 seconds then start up afterwords?

 

Means changing 100uf capacitor and 2K resistor can vary the delay time right? But then what is the role of 22K pot Mr. Dodgydave is saying about?

No! 100 uF capacitor and the 47K resistor,

if you want 2seconds then you need 100uF cap and 20K resistor, so i would put a 22K preset and a 10k resistor in series to give you better results.

 

Adjustability. You can dial in the exact time you want the delay to be.

Quick question for you: You want the motor to run for (oh, lets say) 2 seconds then shut down until power is recycled? Or do you want the motor NOT to run for 2 seconds then start up afterwords?

Yes I want the motor to run for 2 seconds then shut down until power resets.

 

Why 2 seconds? Can you live with 4 or 5 seconds or slightly longer? How tightly are you constrained to 2 seconds?

[edit] Well I suppose that's a moot point. With the circuitry DodgyDave gave you - that should solve your problem. You can precisely dial in the delay with the pot.

 

Why 2 seconds? Can you live with 4 or 5 seconds or slightly longer? How tightly are you constrained to 2 seconds?

[edit] Well I suppose that's a moot point. With the circuitry DodgyDave gave you - that should solve your problem. You can precisely dial in the delay with the pot.

Yeah 2 second is not necessary 5 seconds will work fine.

 

No! 100 uF capacitor and the 47K resistor,

if you want 2seconds then you need 100uF cap and 20K resistor, so i would put a 22K preset and a 10k resistor in series to give you better results.


View attachment 126930

OK I will try this. Thanks for help

 

Here's a circuit I built a long time ago. Have a truck (standard transmission) with cruise control. The transmission would not shift down on its own when the load got too heavy, so I put in a vacuum gauge to know when the load was too heavy, and I could shift down. The gauge had a memory and you could set the color to match your gauges. Every time I started the truck the gauge would light up then default to the factory color. Hated having to choose the color every time I started the truck. So I built this circuit to delay the onset of power going to the gauge. Delay was about 4 seconds. You can use this to incorporate the relay as a delay ON or a delay OFF.

[edit]
And yes, I used a 24 volt relay. At 13.6 volts it would easily click in. You may want to modify the circuit to suit your needs, but this is a very cheap base to start from without having to build the 555 timer circuit. The advantage here is there are no IC's to be harmed by Electro Static Discharge. Oh, and the relay is shown in the energized position.

 

Followup thought on the circuit I provided: if you're powering the relay from a low voltage source such as 12 volts and want to switch a motor running at high volts AC then the relay you'll want to use will have to be a double pole double throw type so you can isolate the high voltage from the low control voltage circuitry.

 

Followup thought on the circuit I provided: if you're powering the relay from a low voltage source such as 12 volts and want to switch a motor running at high volts AC then the relay you'll want to use will have to be a double pole double throw type so you can isolate the high voltage from the low control voltage circuitry.

But your circuit isn't using 555 IC. I want to built whole circuit with 555 IC only. Thanks for advice.