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Hi Folks,
I'm working with MT8870 to turn on the water pump using cell phone. The circuit works fine but there is small issue. Here are few things about my circuit,
1. The output (Pin. 11) stays latched which helps to hold relay on continuously until it receive another tone. Relay operated by...
Yes you are right. By Powering Off the from the circuit, the 555 operated relay gets ON for few micro second. The protection diode is soldered across Relay and 555 Pin 5 grounded with cap 0.01 MF & pin 4 is also grounded with R (10K)-C (0.1 MF) combination to ensure always OFF state of 555...
Thanks for you support guys. Now I've removed the Green relay and I'm using 2N3904 with 10K base transistor directly to flip-flop the 555 output. The chattering problem is gone. But there is only one issue that on the quick power ON/OFF cycle 555 output gets ON & OFF (this is unpredictable)...
Hello Guys,
Here is my ckt explanation,
- Yellow circle area has an astable 555 ckt with small 2 sec buzzer. This is fitted which will be activated once the pump activated & user can hear buzzer sound & confirms that the pump is started running.
- Blue circle has DTMF 8870 which is decoding the...
Yes, I've connected protection diode across relays already. I'll try 1K and will let you know the results.
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My circuit is almost ready and working well but only the problem is if I press and hold button (accidently) more than 1sec (I guess) the relay gets ON initially and...
I've connected DTMF decoder 8870 which turn on 5v relay first. Then that relay is used to switch the button which was shown on pervious 555 toggle circuit. And finally 555 output is used to switch another 5v Relay to operate water pump motor. My basic intention of this circuit is to ON & OFF...
I'm using attached circuit to switch 5V relay. instead of using resi.1K and transistor 2N 3904 I'm using resi. 100 ohm and transistor 2N2222. But the issue with the circuit is that when I press button relay gets ON and stays high even after releasing button and gets OFF when I again press the...
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