AC filter circuit, the primary one-dimensional filter adapter

ATX power principle

Effects of components:

F1: Fuse overcurrent protection, when the phenomenon of slow power line through F1 increase its lead wires will flow, disconnect the power supply to protect the components are not damaged further.

TH1: Overvoltage protection fuse, which are composed of one pair of adjacent semiconductor, its maximum voltage of about 230V-270V (depending on source). When the voltage is too high or lightning voltage leads to higher on TH1, this junction will break to interrupt the supply voltage for the power supply.

CX1, CX2: Capacitor input filter, short circuit the pulse of industrial noise frequencies.

LF1: Inductors, prevent impulse noise frequencies to reach the source.

RV/C3/C3: RC type filter circuit make way for high-frequency pulses.

D1-D4: Circuit bending, variable AC voltage supply DC voltage.

C5/C6: Source filter capacitors, voltage smoothing circuit bending.

R1/R2: Resistor balance the voltage across the two capacitors.

SW1: Power switch input voltage changes. 220 - interrupts, 110V - closed.

Alternating current passes through the fuse, remove noise pulses by RV CX1/LF1 to. Filter circuit including RV/C3/C4 will continue removing remaining industrial interference. In other words, the AC adapter to demand cleaner.

Since the AC voltage is constantly changing so the adapter needs to change. Eg forward selling 1 A (+) / B (-), sale of 2 A (-) / B (+) ...

If the input voltage is 220V (SW1 off).

A (+) / B (-), the D2/D4 diode is biased, the current passing from point A through D2, loaded for pairs of capacitors C5/C6, via download mass, through D4 back to the point B, closed circuit.

A (-) / B (+),, diode D1/D3 polarized agreement, the current passing from point B through D3, loaded for pairs of capacitors C5/C6, through downloading mass, D1 back to point A, closed circuit.

So, with the second semi-period of AC line are creating an over load current from top to bottom. Voltage applied to the capacitor pair will have positive (+) at point C, negative (-) in D (mass). Voltage on C5/C6 values ​​are:

- (220V-2x0.7) x sqrt2 = 309.14 V (if you use silicon diode, the voltage drop on each diode ~ 0.7V)

- (220V-2x0.3) x sqrt2 = 310.27 V (if used germanium diode, the voltage drop on each diode ~ 0.3V)

If the input voltage is 110V (SW1 play)

A (+) / B (-), D2 is biased, the current passing from point A through D2, loaded for C5, on B closed circuit. The value of voltage on C5: 110V-x0.7) x sqrt2 = 154.57 V (due to the diode voltage drop of 1)

A (-) / B (+), D1 is biased, the current passing from point B to load for C6, D1 to A closed circuit. The value of the voltage across C6 is: (110V-x0.7) x sqrt2 = 154.57 V (due to a pressure drop of 1 diode).

The total voltage on C5/C6 will be: 154.57 x 2 = 309.14 V

This is the primary source of one-way circuit provides full source, the workers used to call the voltage on point A voltage is 300V, of course, so as not accurate in terms of value.

The damage in the circuit:

Phenomenon 1: Insert the fuse

- Due to over voltage, lightning. Instead of the right type.

Two phenomena: an end to fuse, instead it off.

- Because short 1, 2, 3 or even 4 diode bridge adapter. Then measure the resistance forward / reverse of them are ~ 0Ω. Instead.

- Due to the short one in the filter capacitor. Measure will see the impedance of 0Ω, replace. However, this causes extremely infrequent (1% probability).

Note: 1 Some sources also have torpedo tubes (shaped like ceramic capacitors) surge protection parallel fuses F1, lightning or high voltage, it will short increase and cause broken line fuse F1 . If the source uses this type of protection, you will have to check the impedance measured by 0, instead.

Phenomenon 3: A low voltage from 220V-250V.

- Do one or both 2 dry filter capacitor. Instead.

When dry capacitors will usually accompanied by the phenomenon of the machine will not start or boot, but Reser, hanging by sources at the time was not filtering technology, also lead to the source of AC ripple.