I need to at least delay my LED. I'm ONLY allowed to use BJT and resistors. ( No Diode, Relay, Capacitors and IC's etc.) Details: there are 7 LEDS in total. There are 7 levels in the container which the led's indicate. If the container is "empty" the 1st led is "on". If the water reaches to the 2nd led/level, "on" and the 1st led will turn off. 3rd led/level = On ; 2nd and 1st = Off 4th led/level = On ; 3rd, 2nd, 1st = Off 5th led/level = On ; 4,3,2,1 = Off 6th led/level = On ; 5,4,3,2,1 = Off If the water reaches to 7th led/level all led's is "Off" but after a delay in (secs, milliseconds) all the leds will turned "On" I need any kind of help or advice to do this project. thankyouu! |
by amsnklmf
March 13, 2019 |
resistor and transistor don't have delay function. |
by wangwg88
March 13, 2019 |
Please help |
+1 vote by amsnklmf March 13, 2019 |
I couldn't attach picture of circuit. you can tell me your email. |
by wangwg88
March 19, 2019 |
you may use millions pieces of BJTs and resistors to make the delay circuit, but it never happens in actual circuit. |
+1 vote by wangwg88 March 17, 2019 |
Needs a timer circuit on the output to LED 6 so when it goes off (LOW), the timer is initiated, then "enables" all LEDs after a pause. Difficult to be more exact without seeing a circuit diagram Have a look at 555 timers. |
+1 vote by Negativ3 March 23, 2019 |
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