so ive been using this relay circuit for most of my projects
since its so simple and unobtrusive. i found out the hard way the way implemented it.. doesnt work! i blew a tr in my baksa 55 amp, 35v rails, and the relay didnt shut off. in fact, it turns on even faster than before with 33v present on r36. this is the first time i actually got to test out the relay, and i've paid for my ignorance dearly.
the circuit specifies 24v but i've been feeding it 35v+.
what can i change it to make it work for my baksa? i'd like to use the raw rail voltage which's still 35v
thanks in advance
since its so simple and unobtrusive. i found out the hard way the way implemented it.. doesnt work! i blew a tr in my baksa 55 amp, 35v rails, and the relay didnt shut off. in fact, it turns on even faster than before with 33v present on r36. this is the first time i actually got to test out the relay, and i've paid for my ignorance dearly.
the circuit specifies 24v but i've been feeding it 35v+.
what can i change it to make it work for my baksa? i'd like to use the raw rail voltage which's still 35v
thanks in advance
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If the relay itself draws less than around 100ma (measure the coil resistance in ohms and divide it into 24) then you could try a series 1.3 watt 12 volt Zener in the supply. That would drop 12 volts.
Even a series resistor would probably be OK. Yes, you would tend to see the full supply when the relay wasn't activated but that would fall when the relay was on. Again ohms law. You need to lose around 12 volts and so R=V/I where I is the relay current at 24 volts. Wattage would be 144/R.
Even a series resistor would probably be OK. Yes, you would tend to see the full supply when the relay wasn't activated but that would fall when the relay was on. Again ohms law. You need to lose around 12 volts and so R=V/I where I is the relay current at 24 volts. Wattage would be 144/R.
I think you don't need R16 and R36 in this circuit ..... and you can use LM 7824 regulator to get +24V voltage for protection ! Tray without those resistors. DC voltage on R16 and R36 feed base of Q2 and will turn ON relay, just think . See below attachment ....
BR Alex
BR Alex
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Normaly the relais is turned on and to much DC on the speaker makes the relais turn off.
For positive DC it should work but negative DC needs a much bigger R21.
How much bigger depends on de supply voltage. With +24V 470k and with +35V 680k.
The idea is to feed no more current to the base of Q2 then a faulty negative DC can draw away.
Mona
I wouldn't call a series Zener 'a regulator' and it certainly won't add any noise anywhere.
Hi,
After more investigation on the DC protection module, I have found an interesting solution here : My_Ref Fremen Edition - Build thread and tutorial therefor I have redesigned my protection module...
Not tested yet however
Marc
After more investigation on the DC protection module, I have found an interesting solution here : My_Ref Fremen Edition - Build thread and tutorial therefor I have redesigned my protection module...
Not tested yet however
Marc
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