Hi everyone,
I'm studying a product , when I opened it I found a set of 6 SMD resistors connected in series and want to know why to add 6 instead of 1 or 2.
the circuit is a delay-on timer, it uses 220VAC mains voltage, the circuit uses a capacitive divider to decrease the voltage to 20V, the circuit contains a relay; so to avoid the increasing of the voltage they put 6 resistors as a load when the relay is off so the same current flow and the same voltage will still.
when dividing the 20V by (6*270ohm) resistors we get 3.33V across each resistor and the dissipation in each resistor is about 0.04W, but here they uses 0.125W SMD resistors.
1- Sorry because I haven't the full schematic of the circuit.
2- why do they use 6 resistors instead of 1 or 2 equivalent ? (I know when dealing with high voltages they prefer to connect more than one resistor to avoid humidity of any thing that may destroy the circuit, but why 6 !!!)
3- why the resistors size is 3 times the required size? (SMD resistor with 3.2mm length, 1.6mm width).
Thanks.
I'm studying a product , when I opened it I found a set of 6 SMD resistors connected in series and want to know why to add 6 instead of 1 or 2.
the circuit is a delay-on timer, it uses 220VAC mains voltage, the circuit uses a capacitive divider to decrease the voltage to 20V, the circuit contains a relay; so to avoid the increasing of the voltage they put 6 resistors as a load when the relay is off so the same current flow and the same voltage will still.
when dividing the 20V by (6*270ohm) resistors we get 3.33V across each resistor and the dissipation in each resistor is about 0.04W, but here they uses 0.125W SMD resistors.
1- Sorry because I haven't the full schematic of the circuit.
2- why do they use 6 resistors instead of 1 or 2 equivalent ? (I know when dealing with high voltages they prefer to connect more than one resistor to avoid humidity of any thing that may destroy the circuit, but why 6 !!!)
3- why the resistors size is 3 times the required size? (SMD resistor with 3.2mm length, 1.6mm width).
Thanks.