Hero999
Banned
Do you have a multimeter?
Measure the supply voltage, does it read 12V?
What are you using to power thing with?
Is it an unregulated 12V mains power brick?
Some of these can output voltages as high as 20V with a light load, if so your 555 only has an absloute maximum voltage of 16V and might be destroyed.
Measure the voltage on the capacitor, does it reach 0V pretty quickly when the power is removed and charge up more slowly when the power is applied?
Are you using the correct resistor can capacitor values? Measure the resistor with a multimeter to make sure. I doubt you're using 500k which is a non-standard value, unless it's a pot.
Your origional post said you require a delay of 10 seconds, the components values you have chosen only give about 5 seconds.
Try replacing the capacitor with 100:mu:F and the resistor with 47k or 100k depending on whether you want 5 or 10 seconds. Somtimes the leakage capacitor current can be too high so it never charges though the high value resistor.
If I remember rightly the 555 supplied in the Maplin kit is a TS555 and can only drive 100mA; are you sure your relay uses less than this?
You can easilly test a 555 timer by building an astable that flashes an LED but the circuit is just as complicated as this one which you are having trouble building so I wouldn't recommend it.
Put the circuit and all your components away and return to this problem another day when you've rested.
Measure the supply voltage, does it read 12V?
What are you using to power thing with?
Is it an unregulated 12V mains power brick?
Some of these can output voltages as high as 20V with a light load, if so your 555 only has an absloute maximum voltage of 16V and might be destroyed.
Measure the voltage on the capacitor, does it reach 0V pretty quickly when the power is removed and charge up more slowly when the power is applied?
Are you using the correct resistor can capacitor values? Measure the resistor with a multimeter to make sure. I doubt you're using 500k which is a non-standard value, unless it's a pot.
Your origional post said you require a delay of 10 seconds, the components values you have chosen only give about 5 seconds.
Try replacing the capacitor with 100:mu:F and the resistor with 47k or 100k depending on whether you want 5 or 10 seconds. Somtimes the leakage capacitor current can be too high so it never charges though the high value resistor.
If I remember rightly the 555 supplied in the Maplin kit is a TS555 and can only drive 100mA; are you sure your relay uses less than this?
You can easilly test a 555 timer by building an astable that flashes an LED but the circuit is just as complicated as this one which you are having trouble building so I wouldn't recommend it.
Put the circuit and all your components away and return to this problem another day when you've rested.