Please suggest a time delay toggle switch

This is only part of my switching circuit, If you press it again, other parts of the circuit would turn it off. That is correct, I did post a similiar question before, people in that forum are very helpful. However, some expert posposed very helpful suggestion. Cause I didn't mention I need the status remain until press it next time. Therefore I post that query again. Thanks for any advise.

Get a 74HC74, a 74HC14, and a SPDT switch. Connect 2 sections of the 14 in series. Connect the output of the second stage to clock of the 74. Connect a 100 uF capacitor from input of the first 14 to ground. Connect the common terminal of the switch to the same. Connect a 560K resistor from the NO terminal of the switch to VCC. Connect a 100 Ohm resistor from the NC terminal of the switch to ground.

Tam

Thank everybody. Your information is really helpful. I need to work out Fred's advise for evaluation. Answer some question. First, the 5 second not necessary to be accurate, can be 3- 5,6 second, jsut obviously longer that momentary. Second, Bacause other chip are 4XXX, in order to make it consistance. Thirdly, There is a clock signal at around 100Hz from other flip-flop, it can be use in case it is necessary. I studied some book, I found the D-type FF (4013) can be used as Toggle switch, one as monostable and other as bi-stable. How can it be connect to toggle once press the button and change state while press for 5 second to toggle the bistable FF's output?

--
If you\'d tell us _exactly_ what you want, from beginning to end, and
what your application is, we\'d probably be able to help you and you
wouldn\'t have to keep posting the same series of seemingly
disjointed posts over and over.

What happens if you press the button again, and hold it for another 5 seconds?

Didn't you ask this a while back ?

Graham

What design specification is driving the requirement that the device be implemented with 4000-series CMOS parts?

Does the design include any clock signals?

How accurate is "5 seconds?" More than 2 and less than 10 or within

+/- 1 microsecond or ?

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Rich Webb   Norfolk, VA

I am assume here the main catch is you want to terminate the toggle operation for switch closures of less than five seconds and activate the toggle operation at the five second time even though the switch may still closed. The breakdown into generic and well-known logic functions would look something likes this: View in a fixed-width font such as Courier.

. . . . +--------------------------------+ . | | JK FF . | | +---------+ . ---- | MONSTABLE +---|J Q| . | | +--------------+ | | | . | | | ___ | | | | . SW | >---+---|>CLR OUT |-------------|---|>CLK | . | | | | | | . --- | | -- -- | | | . +--------------+ | | | | _| . | | +---|K Q| . --- +---------+ . . 5 SECS . . . ^ . MONOSTABLE retriggers each | edge from SW and clears when SW='0' . .

Be careful about firing a monopulser from a switch. The switch closure can result in multiple pulses. You will have to

A logic '1' on both JK makes it toggle state on the positive going clock transition, a '0' on JK means no state change on the positive going clock. The only time the JK inputs will be '1' while the clock makes a positive transition is when SW has been closed continuously for 5 seconds.

I don't know what happened. Did not mean to send that. Intent was that any monopulser pulse be wider than bounce time of perhaps 10 milliseconds. I do not know what the MP is supposed to do, other than delay the switch by 5 seconds. I think the HC14 schmitt trigger idea works better.

Tam

Actually, my turntable only palys 33. I want to add another oscillator make it plays 45 as well. There is only one button on the panel. Therefore, I want to press the button to turn on the 33 , then press the same button a little bit longer to toggle to another oscillators. I can use the FF output Q and "Not Q" to toggle from either oscillators. Of course when you press the button again, it turn off the turntable.

Hi Ed, Thanks again for your information. The 5 seconds switch works very well. I can make use of it to work on other circuit. Certainly, your 4017 works in my application. May I ask what is the different between a toggle FF like 4013, 7474..etc in camparision with the 4017 decade counter ? In consideration of reliability, durability, stability ..etc. which one would you choose? I think I am going to test all different suggestion to see the result.

You were saying...?

In the earlier thread, you indicated that the 5 second circuit worked for you, so you can use it again. I assume the decade counter circuit also worked. Use the same decade counter circuit (with one change) and the 5 second delay circuit that were posted in response to your earlier posts. The 5 second circuit increments the count stored in the decade counter by + 1 after the switch has been pressed for 5 seconds. The difference between this decade circuit is that you will use

2 to reset it instead of 3. So the possible states of the decade counter are 0 and 1. If the counter is at 1 and you press the button for 5 seconds, the count increments by + 1 and goes to 2 - but 2 resets the counter

Ed

Go on, go on! I'm on tenterhooks here

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Terry Pinnell
Hobbyist, West Sussex, UK

The only consideration is identifying circuits that you are comfortable with. Since the decade counter and 5 second timer both work for you, stick with them.

Later on, you can experiemnet with other circuits and get comfortable using them. For example, experiment with the J-K flip flop that Jim Thompson recommended in the other thread, and the the R-S flip flop to learn to avoid the illegal input state.

Ed

Absolutely correct. One button selection is really limited. However, this application is only for my turntable. I can get used to it. i.e. press the button to "On" 33. Press again, "Off". While play 33 want to switch to 45. Turn it off, then press the button long enough to toggle

45 oscillator. I think I got a workable circuit on my bread board now. Question, how to feed two oscillator output to op-amp circuit. The existing circuit has a 22K resistor connected to 4013 clock output pin 12 (pin 12 connected with pin 5), 22 K is then connected with 5K VR to set level. and other end of 5KVR connected with a 22U cap. to ground. Output of 5K VR connect to LM324 via a 56K resistor. Since I duplicated the same oscillator, can two oscillator ouput connect to the same op amp input?

and...

That is not the same as your original:

With one button, you don't want it to work like that. You use the single button to make one of three state selections: 33, 45, or OFF, and the circuit activates the setting something like 3-5 seconds after last button *release*- and NOT when the selection is actually made with the button press.