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# Making a timer on delay and off delay without microcontroller

##### New Member
I am new and want to make a compact circuit without a microcontroller. The idea is when you push the button/switch, it will delay the timer for at least 6 hours. After that, it will activate the motor for 20 seconds and loop forever. I am thinking of using a 555 timer with a 1000uF capacitor here, but it fails miserably. Any ideas?

They are pull down and pull up resistors.
I looked at the datasheet but couldn't figure out the calculation for C2 and R3 on the 4013. How do you get 330k? By the way, thank you so much for your help and to everyone who assisted me. Love you all!

In your schematic you have R8 asking, essentially, for >> 10 mA, thru LED, schematic
in post #38. The min output is speced at ~ just a little over 1 mA (with a Vo achieving
a logic "1" with margin). One cannot tell from datasheet how if excessive current, low
V, is going to be a problem internally to part. You can get LEDs at 2 mA that are pretty
bright, which would translate to a R8 value of ~3.5K (assuming red LED Vfwd is ~ 2V).

Regards, Dana.

I looked at the datasheet but couldn't figure out the calculation for C2 and R3 on the 4013. How do you get 330k? By the way, thank you so much for your help and to everyone who assisted me. Love you all!
I use this equation:

T = -ln((V-Vc)/V) x R x C

Where:
V = Supply Voltage = 12
Vc = Target voltage = V x 0.7
T = Delay (seconds)

fadlianturu6 If you acknowledge (ACK) what you are given to learn with a Like, then we know you understand. If no reply, say what you do understand (NAK) and why not. Otherwise I will assume you understand. Then it is up to you to give feedback. In digital communications it is critical and is often described as ACK/NAK choices. So please ask a better question with your assumptions. We all had to learn every parameter of datasheets to understand.

Otherwise this thread will take a hundred comments for you to succeed.

1. Is that OK with you?

Given the experts in the semiconductor datasheets have told you this, there are reasons for your errors and supplier error tolerances.

2. When using 10 Meg, what is your equivalent Rp of your Capacitor?
3. What is the Vcc, f measured of CLK and computed f and % difference . Also what is duty cycle error from 50%, as I explained this due to input threshold normal variances and affects time interval of two exponentials NOT One..
4. CD4xxx series CMOS is called high voltage and that also means high output impedance. COnversely if you used 5.5Vmax logic family 74HCxx, it means low impedance (50ish ohms +/-33%?) and 3.6V family max, even lower Vol/Iol=Zo
6. Can you measure Rp leakage time with a 10 Meg scope probe? What is your cap parallel leakage, equivalent V/I= Rp?
What is it when the polar cap voltage is negative?

There are 1st order approximations for everything like T 2.2 * RC.
Then there are 2nd order approximations and 3rd order
and then there are wildass quesses

For CD4xx imagine RdsOn is 10Kohm at 9V or check datasheet and compute nominal Vol/Iol , output low and interpolate if using Vdd=9V

For 74HCxx family assume RdsOn or Zout is 50 ohms at 5V or verify with datasheet for nominal Vo min/max at I close to what you are using or use max current.

7. I am assuming you know how MOSFETs work and what RdsOn means
ok?

When something fails, check every pin onthe device for clues to reasons why, if you do not understand why, and report them
8. OK?
any ideas

how i tag you guys without this quote
Type @ then the first few letters of the persons name and select from the menu.

Several working designs have been given to you by experts and some had differences like Turn on Output in 1st 20 seconds then cycle 6 hrs, others was reset, wait 6 hrs run 20 sec then repeat.
"As you defined in your "spec" OK? no problem
Just verify every pin is correct and each IC is working as it should, according to your understanding.
1st Vcc, ground , no floating inputs.
2nd check clock voltage, time interval and load voltages on every output.. correct errors, continue....
3rd ...ok got it?

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