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6v relay problem

barathbushan

Sep 26, 2009
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hi i am new to relays , i have this relay which i want to drive using a transistor , whose base is connected to the output of 555 timer , timed at 1 second , the emitter is grounded directly , and the relay is connected between 5v supply and the collector , with a diode connected to dissipate the counter emf of the coil , the above circuit i mentioned is not working , i hear clicks of the relay but still is not working , i changed the relay , it was still of no use .

what could be the problem , can it be the 5 volts supplied to a 6v coil ??

also please tell me the maximum and minimum values can a relay rated at 6v can take .

Thanks !!
 
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Laplace

Apr 4, 2010
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Let's assume you are using a Panasonic HC relay. Go to the Panasonic relay page at http://pewa.panasonic.com/components/relays/power-relays/general-purpose-power-relays/ and download the HC catalog: http://pewa.panasonic.com/assets/pcsd/catalog/hc-catalog.pdf

Find the HC relay data for the 6 VDC nominal coil voltage on page 3 where it states that initial pick-up occurs at 80% of nominal voltage with a maximum rated voltage at 110% of nominal.

But my question is: If the relay clicks, how can you tell that it is not working?
 

barathbushan

Sep 26, 2009
223
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dm4p3m.jpg


i mean it clicks spontaneously , not when switched by the transistor , the relay works properly if when connected connected and disconnected from battery [manual switching] , but it cannot be
switched by a regular npn , like i have shown in the circuit . also the relay that am using is a 6 volt
goodsky rw-sh-106d relay .
 
Last edited:

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
25,510
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Without a base resistor, you have probably toasted the base-emitter junction
 

barathbushan

Sep 26, 2009
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well , i have not used any base resistor for the first transistor which drives led's , and it works fine , but why should i use the resistor for the second trransistor ??
 

Laplace

Apr 4, 2010
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If any of those LED's light up, then you can be sure the relay transistor is toast. If that transistor were good there is no possible way for the LED's to glow because the base of the LED transistor would never exceed 0.6 volts.
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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Start with something like 1k.

It may also be wise to grab some new transistors too.

There are other faults with your LED circuit too, bit that can wait.
 
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