muddasserniaz

i have built this 4541 single shot timer ranging from 15m to 8hrs. The output remains low and goes high after set time.

How can i get notification that oscillator /circuit is working properly when the timer starts.???

regards

Attached Images

4541 sch copy.jpg (214.4 KB, 45 views)

k7elp60

I don't understand why you have a resistor from pin 6 to ground. The spec sheet says it should be at 0 for timer operational or 1 for master reset. Since you have it programmed for power up reset and single cycle operation, you can assume with the output a 0 it is functioning properly when you apply power. I would recommend that you only change the dip switch setting for capacitor selection when the power is off.

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Roff

You could monitor the internal clock with a small MOSFET (2N7000, 2N7002), an LED, and a current-limiting resistor. Gate to pin 3, source to GND, drain to LED-resistor series combo, other end of LED-resistor to VCC.

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Ron

muddasserniaz

thanks ron , oscillator monitoring led is working great with 2n7000.. !!

i have some more questions regarding 4541 operation.. plz help!!

1) what's the lowest frequency possible/recommended , although datasheet says the fx should be between 1khz and 100khz i have used it at 1hz and its still working ....but when fx is lower than 1 it is not working.

some say that 4541 can be used for timing delays of days but i am not sure how it can be achieved without fx lower than 1hz.

2) keeping in view the component tolerances how can i achieve best accuracy??

Roff

Sorry, I've not used the 4541. Maybe someone else can help.

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Ron

k7elp60

For accurate long time delays I would use a CMOS 555 as you can use up to about 20M of resistance for timing. But use a good quality film capacitor. You could still use the 4541 divider. I have used the 555 and cascaded 4060 14 bit counters for extreemly long delays.

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The great thing about electronics is unlimited ways to do the job. The only limit is one\'s imagination. I generally think my way is best.
Show me a different way. I have an open mind.

audioguru

The datasheet for the CD4541 says you can operate the clock oscillator as slowly as you want. Then you can use its divider to divide by up to 65k.

Attached Images

CD4541.PNG (16.5 KB, 4 views)

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Uncle $crooge

mvs sarma

Hi
i understand your doubt as how to know the cct is functioning or power failed --something-- in fact you might have notices that 4541 can output either Q or Q*
if you select by defining the select pin you get a high sinal when the timer is ON . Hope this helps

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Sarma.