variable 5,10,15,20 minutes timer circuit - Electronic Circuits Projects Diagrams Free

james · 22nd October 2002, 04:12 AM

i'm here again. Could you please help me make this circuit 5,10,15,20 -minute timer. i've already searched many sites and i have to make certain modification to suite my need. I used 555 timer and varies R and C values. I like to have others design. thankst

thec · 22nd October 2002, 04:27 PM

Buy a 4 stage switch, set up the resistor loads per switch mode which set up the timer values of the 555 and go for it?

OR put in a potentiometer and make it variable, but that maybe isn't accurate enough for your needs?

//Albert "thec" Sandberg

pebe · 24th October 2002, 06:00 AM

Quote:

Originally Posted by thec

Buy a 4 stage switch, set up the resistor loads per switch mode which set up the timer values of the 555 and go for it?

OR put in a potentiometer and make it variable, but that maybe isn't accurate enough for your needs?

//Albert "thec" Sandberg

You would be pushing your luck trying to get a 20minute delay from a 555. You need to make it drive a counter of some sort. eg, a 4006 or similar.

thec · 24th October 2002, 03:24 PM

Ooops, I instantly thought of seconds :-)

Yeah, would do. you could easy combine 555 with a counterchip...

//Albert "thec" Sandberg

taranakiguy · 15th January 2009, 09:31 AM

Descriptipn:
A switched timer for intervals of 5 to 30 minutes incremented in 5 minute steps.
Notes:
Simple to build, simple to make, nothing too complicated here. However you must use the CMOS type 555 timer designated the 7555, a normal 555 timer will not work here due to the resistor values. Also a low leakage type capacitor must be used for C1, and I would strongly suggest a Tantalum Bead type. Switch 3 adds an extra resistor in series to the timing chain with each rotation, the timing period us defined as :

Timing = 1.1 C1 x R1

Note that R1 has a value of 8.2M with S3 at position "a" and 49.2M at position "f". This equates to just short of 300 seconds for each position of S3. C1 and R1 through R6 may be changed for different timing periods. The output current from Pin 3 of the timer, is amplified by Q1 and used to drive a relay.

Parts List:

Relay 9 volt coil with c/o contact (1)
S1: On/Off (1)
S2: Start (1)
S3: Range (1)
IC1: 7555 (1)
B1: 9V (1)
C1: 33uF CAP (1)
Q1: BC109C NPN (1)
D1: 1N4004 DIODE (1)
C2: 100n CAP (1)
R6,R5,R4,R3,R2,R1: 8.2M RESISTOR (6)
R8: 100k RESISTOR (1)
R7: 4.7k RESISTOR (1)
Circuit by Andy Collinson
Source: zen's circuit directory

picbits · 15th January 2009, 02:27 PM

I'd have hoped that after 6 years the original poster would have sorted out his problem by now

Its worth checking the date of posts before replying to them.

Welcome to Electrotech by the way

ericgibbs · 15th January 2009, 02:35 PM

Quote:

Originally Posted by picbits

I'd have hoped that after 6 years the original poster would have sorted out his problem by now

Its worth checking the date of posts before replying to them.

Welcome to Electrotech by the way

hi picbits.

The OP has two threads running.

http://www.electro-tech-online.com/e...tml#post684975

picbits · 15th January 2009, 03:05 PM

The OP of this thread last visited this site on .....

2nd November 2002

On the plus side, at least the newbie who bumped this 6 year old thread bumped it with useful information rather than the "Dear Sir, My school project is due tomorrow and I want to design my own nuclear reactor"

ericgibbs · 15th January 2009, 04:12 PM

Quote:

Originally Posted by picbits

The OP of this thread last visited this site on .....

2nd November 2002

On the plus side, at least the newbie who bumped this 6 year old thread bumped it with useful information rather than the "Dear Sir, My school project is due tomorrow and I want to design my own nuclear reactor"

hi,
I'm sorry picasm I cannot help you with your school project for an 'unclear' reactor.

blueroomelectronics · 15th January 2009, 04:32 PM

Aren't those resistors 8.2M x 6 really high for a 555?

ericgibbs · 15th January 2009, 05:47 PM

Quote:

Originally Posted by blueroomelectronics

Aren't those resistors 8.2M x 6 really high for a 555?

I would guess that the leakage current thru the 33uF would be high enough to keep the cap discharged for ever.!

taranakiguy · 15th January 2009, 07:40 PM

Duh Noobie alert! sorry guys only checked the date of the opening post after I posted.... I am learning fast though.

Can anyone help me out at my thread
http://www.electro-tech-online.com/e...tml#post684975

Cheers

BeeBop · 15th January 2009, 08:23 PM

Quote:

Originally Posted by picbits

The OP of this thread last visited this site on .....

2nd November 2002

On the plus side, at least the newbie who bumped this 6 year old thread bumped it with useful information rather than the "Dear Sir, My school project is due tomorrow and I want to design my own nuclear reactor"

Yes, but he did it as a double post:

see this:

Help with 5,10,15,20,25,30 min countdown timer

Edit, wrong quote.

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22nd October 2002, 04:12 AM	#1
james	variable 5,10,15,20 minutes timer circuit i'm here again. Could you please help me make this circuit 5,10,15,20 -minute timer. i've already searched many sites and i have to make certain modification to suite my need. I used 555 timer and varies R and C values. I like to have others design. thankst

22nd October 2002, 04:27 PM	#2
thec	Buy a 4 stage switch, set up the resistor loads per switch mode which set up the timer values of the 555 and go for it? OR put in a potentiometer and make it variable, but that maybe isn't accurate enough for your needs? //Albert "thec" Sandberg

24th October 2002, 03:24 PM	#4
thec	Ooops, I instantly thought of seconds :-) Yeah, would do. you could easy combine 555 with a counterchip... //Albert "thec" Sandberg

15th January 2009, 09:31 AM	#5
taranakiguy	circuit Diagram to try Descriptipn: A switched timer for intervals of 5 to 30 minutes incremented in 5 minute steps. Notes: Simple to build, simple to make, nothing too complicated here. However you must use the CMOS type 555 timer designated the 7555, a normal 555 timer will not work here due to the resistor values. Also a low leakage type capacitor must be used for C1, and I would strongly suggest a Tantalum Bead type. Switch 3 adds an extra resistor in series to the timing chain with each rotation, the timing period us defined as : Timing = 1.1 C1 x R1 Note that R1 has a value of 8.2M with S3 at position "a" and 49.2M at position "f". This equates to just short of 300 seconds for each position of S3. C1 and R1 through R6 may be changed for different timing periods. The output current from Pin 3 of the timer, is amplified by Q1 and used to drive a relay. Parts List: Relay 9 volt coil with c/o contact (1) S1: On/Off (1) S2: Start (1) S3: Range (1) IC1: 7555 (1) B1: 9V (1) C1: 33uF CAP (1) Q1: BC109C NPN (1) D1: 1N4004 DIODE (1) C2: 100n CAP (1) R6,R5,R4,R3,R2,R1: 8.2M RESISTOR (6) R8: 100k RESISTOR (1) R7: 4.7k RESISTOR (1) Circuit by Andy Collinson Source: zen's circuit directory

15th January 2009, 02:27 PM	#6
picbits	I'd have hoped that after 6 years the original poster would have sorted out his problem by now Its worth checking the date of posts before replying to them. Welcome to Electrotech by the way

15th January 2009, 03:05 PM	#8
picbits	The OP of this thread last visited this site on ..... 2nd November 2002 On the plus side, at least the newbie who bumped this 6 year old thread bumped it with useful information rather than the "Dear Sir, My school project is due tomorrow and I want to design my own nuclear reactor"

15th January 2009, 04:32 PM	#10
blueroomelectronics	Aren't those resistors 8.2M x 6 really high for a 555? __________________ Bill Smart Kits build Smart People http://www.blueroomelectronics.com/

15th January 2009, 07:40 PM	#12
taranakiguy	Duh Noobie alert! sorry guys only checked the date of the opening post after I posted.... I am learning fast though. Can anyone help me out at my thread http://www.electro-tech-online.com/e...tml#post684975 Cheers