Time delay

[Mc.]

I have a question and it goes like this: Is it possible to design a monostable that will go to 40 seconds delay.

 

[SYE]

I have an answer and it goes like this: yes

 

[Mc.]

Thanks, but what I actually meant was can it be practical because from the workbench it can work (that I am sure of it).

 

[SYE]

If you want anybody to provide more constructive help you are going to have provide some details of exactly what you are trying to achieve, also details of any external circuitry you might be trying to interface with.
How accurate do you need your 40 second delay to be ?, if it's not critical try googling "555 monostable".

 

[Bob Scott]

SYC has good points. A monostable flip flop set for 40 seconds would be suitable for use in a toy. The 40 second accuracy would be subject to power supply voltage, capacitor tolerance, capacitor temperature drift, capacitor aging, capacitor current leakage, electrical noise etc, etc..

If you need high accuracy, use a stable oscillator and countdown circuits.

 

[Hero999]

If you want to use a 555, go for the CMOS variety and use a tantalum capacitor.

You can also adjust the control voltage (pin 5) to increase the length of the delay.