用LM555整delay circuit

the circuit you found, it functions one-time shot (mono-stable) with time delay only, the timing diagram tells this also. once you press the trigger button, no need to holds the button, it delay a bit and then the output will goes high for a moment, finally it will returns to low, no matter you holds the trigger all the time.

however, if your timing required to push the button for programmable for each on/off. it is still be able use this circuit with a little modification, and you need a bi-stable design,

Pin assignment
1, GND
2, Trigger
3, Output
4, Reset
5, Control
6, Threshold
7, Discharge
8, VCC

the essence of this bi-stable trigger mode, need to ensure the pin2 and pin6 are connected together and biased to middle of VCC.

and then supply the power to a RC network (time constant is about 200K x 1uF something) by the pin3, the Output.

a button switch, can then be short the junctions of RC and the Pin2/Pin6, used as a trigger, limitation about this circuit, greater RC time constant will be less of false trigger from power line surge, also, the bypass capacitor will be always good from VCC to GND

Pin4, RESET, connect to VCC, no need RESET;
Pin5, Control, bypass to GND, most data sheet recommends this;
Pin7, No uses here;

Hope this can be help if I have correct memory and it works for your project.


http://hk.myblog.yahoo.com/xiao-laba

2009-03-29 14:42:27 補充：
pin2 and pin6 are connected together and biased to middle of VCC, it is equally of half of supply voltage power this junction.

yes, then supply the power to a RC network (time constant is about 200K x 1uF something) by the pin3, the Output, it is exactly the description as you have.

由於我唔係幾明白你既要求，大致上你係咪要當你開電後唔係立刻盞燈會着，係要等幾秒鐘正會着，試試將呢幾個圖或修改一下可能達到你既要求。

圖片參考：http://home.cogeco.ca/~rpaisley4/LM555PowerDelay.GIF


其實你只要明白 LM555 既基本動作就好容易作出修改，輸出端可以接繼電器或 LED + 電阻都冇問題架。

圖片參考：http://home.cogeco.ca/~rpaisley4/LM555MissingPulseO.GIF



圖片參考：http://home.cogeco.ca/~rpaisley4/LM555BiDelay.GIF


2009-03-26 18:15:17 補充：
容易啦，不必頭痛，試試現成品，臺灣安良出品，有0.1秒 ~ 600小時，你要幾秒幾小時任你調
http://www.anly.com.cn/english/pdf/AMYN_GB.pdf

2009-03-26 18:16:21 補充：
真既千變萬化架
[email protected]

呢度有tutorial，得閒睇下。
http://www.uoguelph.ca/~antoon/gadgets/555/555.html
你可以參考monostable嗰part，用公式T=1.1xRxC計出10秒的RC值，只用一個trigger(你無須按十秒)，output會轉high，555可以直驅LED，但要加限流電阻。