For make a sconce or a floor lamp with adjustable brightness required at all a little bit of details.
Refer to the diagram in figure 1.
The thyristor VS1 is controlled by diacs VD1. In each half-wave network voltage the capacitor C1 charges through resistor R1. When the voltage across capacitor C1 rises to voltage enable dynistor VD1, it enters an open state. The thyristor VS1 open, as capacitor C1 discharges through the dinistor, and the control input of the thyristor. Changing the resistance of the resistor R1, and changing the charging time of the capacitor, and therefore the time of the thyristor. Thus it is possible to regulate the load power from zero to Uc/2 - Uвк. Where is the voltage network, Uвк - voltage the inclusion of the dynistor. Since the thyristor opens only when a positive half-wave voltage, and adjusting produces up to half the mains voltage. To enable full load may serve as staff switch lamp, shown by dotted lines.
Controller, shown in figure 2, voltage can be adjusted from zero to 100% for less voltage enable dynistor. When switch SA1 scheme works as described above. After turning on the switch SA1 is one half wave voltage is held on the lamp HL1 through the diode VD1, and the other half-wave voltage is regulated by the resistor R1. The voltage regulator according to the scheme of figure 2 can be used for temperature control of the soldering tip. In the latter case, the switch SA1 can perform the function of the inclusion of standby.
When the maximum resistance of the resistor R1 and the off switch SA1 the scheme does not consume current, so no additional switch is not required. A dinistor can be supplied with any letter, but will require selection of the resistor R1 as the voltage the inclusion of diacs different.
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