This example describes a contact -free exchange of automatic compensation regulator , which uses a control transformer secondary voltage to change the compensation voltage to solve power line surge transient phenomenon . The AC voltage regulator AC input voltage 167-264V, output voltage of AC 220 ( 1 soil 5%) V. Circuit works The AC voltage regulator circuit from the power regulator circuit, input comparison circuit , coding control circuit , the output compensation circuit and over voltage / under voltage protection circuit , as shown in Figure 5-40 . Power supply regulator circuit from the power transformer T3, rectifier diode VDl-VD4, filter capacitor Cl-C3 , and three-terminal regulator integrated circuit ICl, IC2 composition . Comparison of the circuit by the input resistor Rl, potentiometers RPl-RP9, capacitor C6-Cl4 and the operational amplifier IC lC3-1C5 formed within the Nl-Ng . Coding control circuit consists of NAND gate integrated circuit IC6-1C8, and non- gate integrated circuits IC9, IClO enamel diode VD8-VDl5, resistors R4-Rll, capacitors Cl5-C22 component . Compensation for the output circuit of the electronic switch IC ICl (Sl-S4), IC17 (S5-S8), thyristor VTl-VT8, compensation for the main transformer Tl, Compensation Vice transformer T2, AC contactor KM and voltage meter PV, ammeter PA Composition . Over-voltage / under voltage protection circuits inside the IC7 non- door D9, diode VD5-VD7, resistors R2, R3, transistor and relay K V component . Vice transformer compensation " for the self- thick transformer , whose role is to provide different Tl a voltage to meet the different secondary Tl compensation voltage . Mains voltage by n buck , VDl-VD4 rectification and Cl filtered all the way through post- Rl -limiting step-down voltage input as detect ; another after passing ICl produced l2V DC voltage regulator , the voltage than the supply IC3-ICl2 , But also regulated by the IC2 to +6 V, as lC3-1C5 ( op-amp Nl-N9) inverting input of the reference voltage . When electricity was higher than 167V, less than 187V , the op-amp high output Nl , N2-N9 output low , AC voltage regulator with compensation using the same approach ( to enhance the output voltage) , connected to electronic switches S1 , S2- S8 is still in shutdown state , triggered thyristor VTl by conduction , T2 of the Wl-W4 winding access circuit , the output voltage will be upgraded to 220V. When electricity was higher than 187V, when less than 198V , Nl and N2 output high , N3-N9 is still low output , AC voltage regulator with phase compensation by way of electronic switch S2 connected , S1, S3-S8 still Off , VT2 triggered by conduction , theT2, W2-W4 winding access circuit , the output voltage is raised to 220V. When electricity was higher than 198V, when less than 209V , NI-N3 output are high , N4-N9 output low , AC voltage regulator with phase compensation by way of electronic switch S3 connected to VW by the trigger and guide Pass, the dish of the W3 and W4 winding access circuit , the output voltage is raised to 220V. When electricity was higher than 209V, when less than 220V , Nl-N4 are the output high , N5-N9 output low , AC voltage regulator with phase compensation by way of electronic switch S4 connected to VW by the trigger and guide Tong , m the W4 winding access circuit , the output voltage is raised to 220V. When the electricity is 220 ( 1 ± 5%) V time , Nl-NS are the output high , N6-N9 output low , the electronic switch S5 connected to VT5 triggered by conduction , and output voltage 220V not Change . When electricity was higher than 231V, when less than 242V , Nl-N6 are the output high , N7-Ng output low , the exchange regulator RP compensation , electronic switch S6 connected to VT6 triggered by Conduction , " the W5 winding access circuit , the output voltage dropped to 220V. When electricity was higher than 242V, when less than 253V , Nl-N7 are high output , N8 and N9 output low , the exchange regulator RP compensation , electronic switch S7 connected to VW by the activation of Conduction , T2 's W5, W6 winding access circuit , the output voltage is reduced to 220V. When electricity was higher than 253V, when less than 264V , Nl-N8 are high output , low output only N9 , exchange regulator RP compensation , electronic switch S8 connected to VT8 guided by the activation of Tong , T2 of the W5-W7 winding access circuit , then the output voltage dropped to 220V. When electricity was higher than 264V when , Nl-N9 are high output , diode VD5 conduction , so that Vl conduction , K Pull , its normally open contact to the work of AC contactor power on KM , KM pull , the normally closed contacts disconnect the AC regulator output voltage is 0 . When the city electricity when less than 155V , Nl-N9 are the output low , diode VD6 conduction , so that Vl conduction , K , and KM pull to exchange regulator output voltage is 0 . Components Selection Rl and R3 are selected lW metal film resistors ; fat , elbow -Rll use 1/4W carbon film resistor or metal film resistors . RPl-RP9 are all made of small organic solid potentiometer . Cl use of capacitors for voltage value of 25V ; C2-C4 and C6-C14 are optional 16V aluminum electrolytic capacitor voltage value ; C5 and Cl5-C22 are selected polyester capacitors . VDl-VM are selected lN4 hundred -7 silicon rectifier diodes ; VD5-VDl5 are selected and 1N4148 silicon switch diode . V use S805O or C8050 silicon NPN transistor . VTl-VT8 pressure values are used for more than 400V Triac , its current capacity should be determined depending on the load power . ICl use LM7812 -type three-terminal regulator IC ; IC2 use LM7806 -type three-terminal regulator IC ; IC3-IC5 were selected type LM324 quad op amp IC ; IC6-1C8 were six non- selected doors integrated circuit type CD4069 ; IC9 and IClO were selected CD4011 type 2 four- input NAND gate integrated circuit ; IClI and ICl2 are used analog electronic switch IC type CD4066 . Tl and T2 should be based on the load of the power to choose ; m use 3-5W, the second voltage l2V power transformer . Use a small DC relay K l2V . KM optional AC contactor or 522 -type intermediate relay ( normally closed contact of their two sets of parallel use) . Circuit Debugging Debugging, first disconnect the thyristor gate (control pole ) and the connection between the electronic switch , the center will RPl-RP9 first transferred to the low potential side . In exchange regulator input is voltage regulator on a manual , step by step to increase the input voltage . When the input voltage falls below 155V when , Nl-N9 are the output low . When the input voltage is 156V , the adjustment RPl of resistance , so that Nl output high . When the input voltage is 187V , the adjustment of RP2 's resistance to N2 output high . When the input voltage , 198V to adjust the resistance of RP3 to N3 output high . When the input voltage is 209V , the adjustment of RP4 in the resistance to N4 output high . When the input voltage is 220V , the adjustment RP5 's resistance to N5 output high . When the input voltage is 231V , the adjustment RP6 's resistance to N6 output high . When the input voltage is 242V , the adjustment RP7 of resistance to N7 output high . When the input voltage is 253V , the adjustment RP8 's resistance to N8 output high . When the input voltage is 264V , the adjustment RP9 the resistance , so that the output high N9 .