Comments on: Dark detector circuit

By: arc_reactor

arc_reactor — Fri, 30 Dec 2011 04:48:56 +0000

thank u very much sir.’;

By: Seetharaman

Seetharaman — Thu, 29 Dec 2011 02:19:52 +0000

Hi arc 104 is 0.1uF (100,000PF) 102 is the correct capacitor. Since the capacitor value is quite high the IC generates squarewave output. Reduce capacitor C1 value and add a 100uF 16volt capacitor across the relay to improve further.
There is no need for any additional transistor to drive the relay as this IC is capable of 200mA drive output.

By: arc_reactor

arc_reactor — Wed, 28 Dec 2011 10:28:55 +0000

susan, a relay is a switch operated by electricity. relays can be driven with a range of 6-24 volts direct current @0.5-2 amperes. the coils of the relay is where you plant the power;.’ you can connect the polarities of the power supply to the coils either way;’ relay, like other switches is classifies by their poles: SPST, SPDT and DPDT. mainly, it is an electromechanical device which is also known as electronic switch;.’

By: susan

susan — Tue, 27 Dec 2011 12:26:17 +0000

what is relay?

By: arc_reactor

arc_reactor — Sun, 11 Dec 2011 08:14:58 +0000

i tried the design as well and i used a 104j mylar cap for c1 1000pf. i did not find a 1m resistor so i used a 1.2m and connected a relay w/c could be driven with a supply from 8-12v i planted the diode across the relay coils yet with or without the presence of light, the relay still goes crazy. it simultaneously switches on and off and i never planted the pot. i even cut off the ldr and i get same results. sir, pls help. what could possibly went wrong?

By: manu

manu — Sat, 03 Dec 2011 09:02:36 +0000

which transistor should be used to connect relay??

By: aditya

aditya — Sun, 20 Nov 2011 12:56:58 +0000

hey..
what is the function of NE555 in the circuit?
can you also tell me what is the capacitor used for?

By: RICK

RICK — Sun, 13 Nov 2011 04:43:11 +0000

I Like Circuit too…OVAISHAMDANI!!!!!

By: Ovais hamdani

Ovais hamdani — Fri, 20 May 2011 21:17:28 +0000

This circt has a bit confusion … I have a simple solution for this …. Hmmm just connect ldr’s 1pin on grnd n second on ic’s 2,6 … N use a prest of 20kr n connet it between vcc n 2,6 … Dun forget to use 100nf’s ceramic capacitor on pin 5 ……… It will really work … I tried

Ovais hamdani

By: Ovais hamdani

Ovais hamdani — Mon, 16 May 2011 15:08:59 +0000

I used this circuit as a security system . 555 ic is great . I made lot of projects on that … Nw m doing diploma n just want to learn assembly language … If u have any curies plz ask to me i like to talk on elctronics … Search me on fb ‘hamdani ovais’ iz my username hope sme1 ll contact to me … Ovais