Question about the 555 timer - Electronic Circuits Projects Diagrams Free

xenoxion · 6th May 2004, 02:00 AM

I'm trying to learn how to use a 555 timer using this tutorial. I think I know the basics, but I'm not sure, so could someone confirm/deny if I'm doing this correctly?

What I think it does is when the trigger is used, the capacitor is charged through the resistor. When the capacitor is fully charged, electricity can no longer pass that way, so the electricity then goes to the output, at which point the capacitor is discharged. Is this correct?

Russlk · 6th May 2004, 02:43 AM

Not quite. The capacitor charges thru the resistor. When the trigger is pulled low, the output goes high and the capacitor is discharged. The output remains high until the capacitor charges to 2/3V, at which time the output goes low and stays low until the next trigger.

xenoxion · 6th May 2004, 03:40 AM

OK, so the capacitor is charged through the resistor, then when low voltage is applied to the trigger, this causes the capacitor to discharge through the output?

Thanks for your help BTW

Sebi · 6th May 2004, 12:10 PM

As You see on block diagram, the pin7 is an open collector, exactly for cap. discharging.

nerosrevenge · 22nd June 2004, 09:55 PM

I'm glad this thread got started it ties in with a project I'm working on. I am using the timer with a trail-camera and I need it to limit the length of time between pictures. Basically I need 12v power for 2-3 seconds and off for 5-10 minutes. If I understand correctly it's the Capacitor that determines the "off" time. Is that correct? I would imagine the value of the resistors will have some effect on that as well. Any suggestions?

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6th May 2004, 02:00 AM	(permalink)
xenoxion	Question about the 555 timer I'm trying to learn how to use a 555 timer using this tutorial. I think I know the basics, but I'm not sure, so could someone confirm/deny if I'm doing this correctly? What I think it does is when the trigger is used, the capacitor is charged through the resistor. When the capacitor is fully charged, electricity can no longer pass that way, so the electricity then goes to the output, at which point the capacitor is discharged. Is this correct?

6th May 2004, 02:43 AM	(permalink)
Russlk	Not quite. The capacitor charges thru the resistor. When the trigger is pulled low, the output goes high and the capacitor is discharged. The output remains high until the capacitor charges to 2/3V, at which time the output goes low and stays low until the next trigger. __________________ see my website: www.geocities.com/russlk

6th May 2004, 03:40 AM	(permalink)
xenoxion	OK, so the capacitor is charged through the resistor, then when low voltage is applied to the trigger, this causes the capacitor to discharge through the output? Thanks for your help BTW

22nd June 2004, 09:55 PM	(permalink)
nerosrevenge	I'm glad this thread got started it ties in with a project I'm working on. I am using the timer with a trail-camera and I need it to limit the length of time between pictures. Basically I need 12v power for 2-3 seconds and off for 5-10 minutes. If I understand correctly it's the Capacitor that determines the "off" time. Is that correct? I would imagine the value of the resistors will have some effect on that as well. Any suggestions?