relay
I'm looking for relay similar to Finder 27.01.8.230 http://www.farnell.com/datasheets/1785142.pdf but with 5V coil voltage.
I'm confused about naming and other parameters. What is the correct name for this relay? Latching/impulse/signal? What does single coil and double coil mean? There are lots of types and parameters and I don't how to choose the right one.
Q1: Yes, it does say Un = 12V DC, Coil resistance R = 27Ω, and Consumption I at UN = 440mA
So, yes if you wanted to drive 16 relays at the same time it wouyld need 16 * 440mA = 7.04A
Q2: "Minimum/Maximum impulse duration: 0.1s/1h (according to EN 60669)"
i.e. it must be triggered for at least 0.1 seconds, minimum
Q3: Are you asking a question about an alternative part, or a "shopping question"?
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If you have access to the ground (more accurately, negative) side of the load, you could probably use a smaller N-channel FET than the P-channel that you have because of the way that FETs work. Something like this:
simulate this circuit – Schematic created using CircuitLab
Don't forget D1, regardless of how you control it. It limits the voltage spike when turning off to a diode drop above the supply by providing a path for current to continue flowing through the inductive load for a (short) while.
If you must control the positive side, then your PFET circuit looks good, except that your R18 is 220 ohms with 12V across it when the motor is on, which comes out to 0.65 watts. With that value, I would not go any less than 1 watt, but you should probably look at a higher value instead.
Best Answer
I think this is a better/simpler solution. The toggling behaviour you get from a flip-flop, in this case a "J-K" 74HC73 which with both inputs wired high, will toggle every time you clock it.
simulate this circuit – Schematic created using CircuitLab
R1/C1 is debounce circuit for SW1, which will cause the flipflop clock to go low for about 50ms each time you press the button. M1 provides drive current (up to 100mA) for the coil of the relay and D1 protects M1 from overvoltage when turning off.
RLY1 has a 5V coil (they're usually about 80mA) and contacts rated for your load. If you need a bigger relay with a coil that draws over 100mA, then use a bigger FET too like an AO3400 or similar.
R4/C3 is the reset circuit, which resets the flipflop to low (output off) on power-up. It will be in reset for about 10ms. D2 will quickly discharge C3 when the power is removed, forcing a clean reset.
C2 is a decoupling capacitor; you put it directly across the power terminals of the flipflop.
Edit: for completeness, I'll assume you may also need help with the 5V power supply. Look for a 7805 and read the datasheet/appnote for that, it will give you a clean 5V to run this circuit from any source between about 7V and 20V. The 7805 will need a heatsink if the source voltage is high and/or the relay coil draws a lot of current, but that's a whole other question and readily googleable.