Hi,
Im busy with some UPS circuit and I need it to switch a couple of relays on then the power is back.
http://www.allaboutcircuits.com/vol_3/chpt_7/5.html
Can I replace the triac with a transistor because I dont want to let the relays on until the power is down,
I basically want a easy method to trigger a couple of relays then the mains is back, currently Im using a 10volt reformer on a 12v relay and if the mains drop the relay drop very fast, but the transformer is to small for 3 relays and then using 3 relays I hear a buzz sounds because it probably under power, in my circuit I have a regulated power supply and a small crap 10 11volt power supply just to do the relay work and the regulated power supply with huge caps is for the timer section and some other components
Purpose needed for:
1 ~ 11 volt - no trigger
12 volt - trigger
thx
Im busy with some UPS circuit and I need it to switch a couple of relays on then the power is back.
http://www.allaboutcircuits.com/vol_3/chpt_7/5.html

Can I replace the triac with a transistor because I dont want to let the relays on until the power is down,
I basically want a easy method to trigger a couple of relays then the mains is back, currently Im using a 10volt reformer on a 12v relay and if the mains drop the relay drop very fast, but the transformer is to small for 3 relays and then using 3 relays I hear a buzz sounds because it probably under power, in my circuit I have a regulated power supply and a small crap 10 11volt power supply just to do the relay work and the regulated power supply with huge caps is for the timer section and some other components
Purpose needed for:
1 ~ 11 volt - no trigger
12 volt - trigger
thx