blueroomelectronics
Well-Known Member
Latching relays are also great for battery operated devices.
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How much contact current can your CMOS relay switch?If you need a relay to operate a device, the current taken by the device will be considerable while the current taken by a relay is very small. Our CMOS relays require 5mA @5v.
The awkwardness of using a latching relay is not worth the effort.
Paralleling relay contacts will not double the current-switching capability, because they will never switch at exactly the same time.my relay switches up to 16Arms (we short both NO legs of relay).
How much contact current can your CMOS relay switch?
He can use one of mine. I need the other one for various tasks.I realise he wants 16 Arms. I have 2 arms, can anyone else help?
Alphadog, see the attached. It will not harm your I/O. In sleep mode your I/O retains the mode and state that is set before entering sleep mode. At power-up, your I/O is set to input mode with no pull-ups, so all bridge transistors will be off. You should put reversed biased diodes across each of the four transistors to protect the transistors against counter-EMF from the relay coil when it is turned off.
Hey Curtis.
Thank you for your help.
I simulated your circuit with QBSR14 (NPN) and QBSR15 (PNP) and received I_RELAY = 5mA.
The Fairchild datasheet for PN2222 says the maximum Vce(sat) at 500mA is 1.0V. Typical is less than 300mV (see Fig. 2).Your simulator doesn't seem to be very accurate. At 500ma a typical 2N2222 can have a drop of up to 1V.