help building a 1 sec on/off circuit

[Gmoney]

Hello, I am in the process of making some test equipment for out lab.

I need to build/buy a circuit that will output a 5V DC signal for 1 second than off for 1 sec and that it would be continuous.

there is a 24VDC and a 5VDC supply already in the test box.

Thank you in advance for your input. I have been reading on this forum for a while and there is a lot of smart people here that are willing to help a fellow out.

G'

 

[ericgibbs]

Hello, I am in the process of making some test equipment for out lab.

I need to build/buy a circuit that will output a 5V DC signal for 1 second than off for 1 sec and that it would be continuous.

there is a 24VDC and a 5VDC supply already in the test box.

Thank you in advance for your input. I have been reading on this forum for a while and there is a lot of smart people here that are willing to help a fellow out.

G'

hi and welcome,
This could be done using a 555 timer in Astable mode2.

 

[MikeMl]

How accurate should the pulse timing be?

 

[Gmoney]

Not so precise i would say, This is going to be used to test that strength of a solenoid while is pulsing.
thanks for your input.

G'

 

[Reloadron]

If you choose to build then the 555 timer as mentioned is a good choice. If you choose to buy then a line like these can be a good choice. You would be looking for a repeat cycle. They have (in some cases) DPDT contacts rated for 10 Amps AC. On some both the off and on time are individually programmable. There are countless manufacturers making them in all flavors. I like the plug in ability.

Also, if you build there are blank small cases available where you can build your own on perf board and insert the board in a blank plug in module. Nice because you can mount your adjustment pots and have easy access. Altech Corp makes some nice din rail mount enclosures.

Ron

 

[Gmoney]

Thanks Ron, I am not sure if these Programmable ones are designed for 5VDC input/output

G'

 

[Gmoney]

Eric, is RV1 k a variable resistor? or a 89.5K resistor?
sorry for the dumb questions.

G'

 

[Reloadron]

Thanks Ron, I am not sure if these Programmable ones are designed for 5VDC input/output

G'

They have a relay output, they also work on a variety of input voltages like 220 & 120 VAC as well as 12 & 24 VDC. The relay output:

Output Contacts:
DPDT 10A @ 240V AC/30V DC,

Ron

 

[ericgibbs]

Eric, is RV1 k a variable resistor? or a 89.5K resistor?
sorry for the dumb questions.

G'

hi G,
Its a variable resistor, I would suggest a 200K pot, this would enable you tweak the timing to 1s On/Off periods.
Most capacitors [2.2uF] have a wide tolerance about their stated values eg: +/-10% or more,, so the pot would be advisable.

Use the 5V supply for the 555 timer

 

[Gmoney]

Thank You Eric, you have been a great help and a good source of knowledge.

I am so glad I found this forum and promise to report back when the test box is completed.

G'

 

[Gmoney]

Hello guys!

he circuit above is working like a charm I am very happy, I need to add a LED to the output so that it blinks on when the 5v 1sec pulse is on. I tried to add one to the output but the LED stays on and keeps the voltage at a constant 3.3VDC or so. please help!!
the LED was connected on pin & and ground

G'

 

[Mr RB]

You need to add a 470 ohm resistor (or 1k might be better) in series with the LED.