using 555 and 4017 to cycle 7 LED's

ScottWang

Joined Aug 23, 2012
7,400
This is what I have so far as a circuit diagram:
View attachment 113211

Would your addition to my circuit work if it was applied to each output of the 4017 after the 2N7000 diode?
In your circuit, no needs to add any diode, because the Led is already like diode.

And you just add 7 circuits that I drew on #34 to the output of CD4017, which mosfet is properly for your application, the first is that you should know the resistance of copper coil and calculate the draw current, to avoid the mosfet turn on and latch, so you should add the Rgs(R1).

If you want to add the led to the circuit then you can using each led in series with a resistor and in parallel with the copper coil.
 

Thread Starter

Tony Spence

Joined Dec 20, 2013
64
You could choose some n mosfet Vgs=4.5V, the Vds≥24V, and Rds(on) ≤20mΩ, Id >= I_coil*3, if you want then you can take R1 away, it still can work fine, how many coil you need to drive then you will need how many circuit as below.

View attachment 112673
Looking at #34 If i did this circuit would i be able to connect all the gates of all the fet's together and then use R1 to connect them to 0v?
 

ScottWang

Joined Aug 23, 2012
7,400
Looking at #34 If i did this circuit would i be able to connect all the gates of all the fet's together and then use R1 to connect them to 0v?
You still didn't mention the current of copper coil and what's the purpose of copper coil, if the copper coil draw the current less than 100mA then you can use ULN2003 or ULN2004 to instead of n mosfet, if the current great than 500mA then using n mosfet is better.

The V/I/R are the basic elements when we discuss with ee, if you didn't provide those then we only can do are guessing, guessing, guessing.

CD4017 --
output "0" → Vg1 of mosfet(Rgs1[10K] connected to gnd) → Vd1 → copper coil1(and diode1)
output "1" → Vg2 of mosfet(Rgs2[10K] connected to gnd) → Vd2 → copper coil2(and diode2)
output "2" → Vg3 of mosfet(Rgs3[10K] connected to gnd) → Vd3 → copper coil3(and diode3)
output "3" → Vg4 of mosfet(Rgs4[10K] connected to gnd) → Vd4 → copper coil4(and diode4)
output "4" → Vg5 of mosfet(Rgs5[10K] connected to gnd) → Vd5 → copper coil5(and diode5)
output "5" → Vg6 of mosfet(Rgs6[10K] connected to gnd) → Vd6 → copper coil6(and diode6)
output "6" → Vg7 of mosfet(Rgs7[10K] connected to gnd) → Vd7 → copper coil7(and diode7)
 

ScottWang

Joined Aug 23, 2012
7,400
Heres a circuit with relays and ULN2004.
Since the n mosfet became more popular and easy to get it, so I don't like to provide any suggestions to use relay in any application of small load , but if the loads are small and much more, to using uln2003 or uln2004 is a good idea and I used that a lot.
 

eetech00

Joined Jun 8, 2013
3,949
Since the n mosfet became more popular and easy to get it, so I don't like to provide any suggestions to use relay in any application of small load , but if the loads are small and much more, to using uln2003 or uln2004 is a good idea and I used that a lot.
I agree. The OP really hasn't said what they want to drive with the 4017. Since the OP did mention relay coil, I thought I'd show an optional circuit using relays.
 

Thread Starter

Tony Spence

Joined Dec 20, 2013
64
You still didn't mention the current of copper coil and what's the purpose of copper coil, if the copper coil draw the current less than 100mA then you can use ULN2003 or ULN2004 to instead of n mosfet, if the current great than 500mA then using n mosfet is better.

The V/I/R are the basic elements when we discuss with ee, if you didn't provide those then we only can do are guessing, guessing, guessing.

CD4017 --
output "0" → Vg1 of mosfet(Rgs1[10K] connected to gnd) → Vd1 → copper coil1(and diode1)
output "1" → Vg2 of mosfet(Rgs2[10K] connected to gnd) → Vd2 → copper coil2(and diode2)
output "2" → Vg3 of mosfet(Rgs3[10K] connected to gnd) → Vd3 → copper coil3(and diode3)
output "3" → Vg4 of mosfet(Rgs4[10K] connected to gnd) → Vd4 → copper coil4(and diode4)
output "4" → Vg5 of mosfet(Rgs5[10K] connected to gnd) → Vd5 → copper coil5(and diode5)
output "5" → Vg6 of mosfet(Rgs6[10K] connected to gnd) → Vd6 → copper coil6(and diode6)
output "6" → Vg7 of mosfet(Rgs7[10K] connected to gnd) → Vd7 → copper coil7(and diode7)

Would i be correct in doing this:
thumbnail_555&4017 first dia edit2.jpg
 

wayneh

Joined Sep 9, 2010
17,498
The use of a gate resistor to source is good form. It ensures the MOSFET turns off in case the 4017 output fails to an undefined state (open, neither high nor low). Mandatory? No. Your circuit will likely work fine without it. If you need high reliability, then give it a thought.
 

DickCappels

Joined Aug 21, 2008
10,171
There is some critical information missing. Until the load is defined, you can't get a decent solution. What is the inductance of and the current through the copper coil and at what frequency do you want to clock the '4017?

This relates to the feasibility of using a 9V battery, what to use as power switches, and what protection is most suitable for your power switches.
 

ScottWang

Joined Aug 23, 2012
7,400
There is some critical information missing. Until the load is defined, you can't get a decent solution. What is the inductance of and the current through the copper coil and at what frequency do you want to clock the '4017?

This relates to the feasibility of using a 9V battery, what to use as power switches, and what protection is most suitable for your power switches.
A boat on the ocean, but there is no target to be reached then where does it going ?
 

Thread Starter

Tony Spence

Joined Dec 20, 2013
64
There is some critical information missing. Until the load is defined, you can't get a decent solution. What is the inductance of and the current through the copper coil and at what frequency do you want to clock the '4017?

This relates to the feasibility of using a 9V battery, what to use as power switches, and what protection is most suitable for your power switches.
How do i measure the inductance of a copper coil?
 

GopherT

Joined Nov 23, 2012
8,009
Would i connect the outputs of the 4017 to the ULN2004 or would i need a new circuit?
You use the exact setup you have for the 555 and 4017, and the ULN2008 is a single chip that replaces all of the diodes (7) and mosfets (7) and resistors (7). Super easy.

Connect the chip to ground and positive power, feed your 7 signals from the 4017 into the ULN2004 and have power to drive relays out of the last 7 pins (internal diodes protects all transistors).
 
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