biboymusic
Member
Hi, can someone help me solve this puzzle? I'm using this very popular LM741 light/dark sensor but can't seem to make it work as it should be. The relay is always HI (on) regardless of the setting of the sensitivity. The only difference from the actual diagram is that I can't find 2N2222 here, so I'm using KSP2222A. Here's the design:
**broken link removed**
I also tried another design:
**broken link removed**
The LED shows that it works perfectly, the response is amazing and the sensitivity does work too. But replacing the LEDS with a relay, it has the same issue with the first design. I noticed that there is a minimum voltage on the LM741 output (pin 6), which could trigger a relay but not a LED.
Please help. I am also open to other designs as long as it drives an LDR, has a sensitivity POT and could drive a relay.
Thank you all!
P.S. ericgibbs maybe you could help me again my friend. Thanks.
**broken link removed**
I also tried another design:
**broken link removed**
The LED shows that it works perfectly, the response is amazing and the sensitivity does work too. But replacing the LEDS with a relay, it has the same issue with the first design. I noticed that there is a minimum voltage on the LM741 output (pin 6), which could trigger a relay but not a LED.
Please help. I am also open to other designs as long as it drives an LDR, has a sensitivity POT and could drive a relay.
Thank you all!
P.S. ericgibbs maybe you could help me again my friend. Thanks.