capacitance value to add delay in circuit

[bobdxcool]

I am using a relay to turn on/off a 12V motor. I wanted to add a delay in the circuit by adding a capacitor across the relay. I wanted to know what value of capacitor should I use to introduce a delay of 1second in the circuit. What is the relationship between the capacitor value and delay value ?


This is the relay I am using, amazon.com/SainSmart-4-CH-4-Channel-Relay-Module/dp/B0057OC5O8 I am activating the relay using a raspberry pi. The raspberry pi is in turn connected to a ULN2803 Darlington array. This is the schematic, i40.tinypic.com/xknc53.png

 

[KlausST]

Hi

Adding a capacitor won't give you a delay, just high inrush current.

To generate a delay you need a series resistor. But doing so with a relay is not a practical solution.

==> the easiest way to add a delay is made with raspberry software.

The next easiest practicable way is to add a RC in the logic data line followed by a schmitt trigger input gate.

Klaus