Simple regulator of capacity (there is a printed-circuit board)
The main advantage of regulators of capacity in which switching of trinistor occurs at the moment of transition of mains voltage through zero - small level of hindrances. To circuit simplification in these regulators apply step regulation of target capacity.
B the device described below as a regulating element is used by p the variable resistor. The number of steps of regulation can be changed from four to sixteen with step-type behavior respectively from 25 to 6,25 %. The minimum of switching hindrances in all range of regulation of capacity provides trinistor inclusion at instant tension of a network about 5 Century
the Schematic diagram of a regulator of capacity on eight steps (i.e. with step-type behavior of 12,5 %) is represented on fig. 1, temporary charts - on fig. 2 Impulses frequency of following of 100 Hz form diode Bridge VD5 of mains voltage... VD8, a chain of R4VD3R3 and the element DD2.1, and a divider of frequency of DD1 lowers it to 12,5 Hz. For change of step-type behavior of regulation it is necessary to increase (or to reduce) factor of division of a divider and in as much time respectively to change size of capacity С1.
of the Fig. 1. Schematic diagram of a regulator of capacity
of the Fig. 2. Temporary charts
Impulses from a divider switch the RS trigger on the elements DD2.2, DD2.3. Tension on a conclusion of the 6th element DD2.3 will increase under the exponential law. At emergence of an individual signal on this conclusion the trigger will be established in a zero condition (on a conclusion 4 elements DD2.3 - a signal 0). On a conclusion of the 10th element DD2.4 there will be a signal of high level which will open the VT1 transistor and VS1 trinistor. Switching RS тригера in a zero condition will occur at the moment of transition of mains voltage through zero. At emergence of individual tension on a conclusion of the 5th DD1 counter through a chain of R1VD2R2 the C1 condenser starts to be charged. At emergence of a signal of low level on a DD1 counter exit the C1 condenser starts to be discharged through R2-VD1-R1 chain. Tension on an entrance of the element DD2.3 decreases, and when it becomes less threshold, the trigger will cease to be switched. Thus, regulating the R2 resistor a ratio of speed of a charging and a C1 condenser discharge, change number of the impulses arriving on base of the VT1 transistor, thereby, regulating capacity in loading from zero (a R2 resistor cursor in the top situation according to the circuit) to 100 % (a cursor in the bottom situation).
On impulse recession on a conclusion of the 6th element DD2.3 the RS trigger reverts to the original state, and the VT1 transistor is closed. Trinistor will be closed by VS1 when the current of loading becomes less current of deduction of a trinistor, i.e. during the moment close to transition of mains voltage through zero.
In the device are used by p resistors MLT-0,125, R2 - SP-1. The R4 resistor make of four in parallel switched-on MLT-2 resistors. The C1 condenser - KM-5б, С2 - K50-16. VD5 diodes... VD8 - silicon with return tension not less than 300 In and an average direct current 10 And. The printed-circuit board of the device is represented on fig. 3.
of the Fig. 3. The printed-circuit board of a regulator
Process of control can be supervised center on the filament lamp which has been switched on on an exit of the device. However it is necessary to consider that for 4-, 8-and 16-step regulators frequency of switching of a current in loading will make 25, 12.5, 6.25 Hz respectively therefore as loading it is possible to use only devices with close thermal inertia (soldering irons, electric stoves, etc.)
the Author: S. ZOLOTARYOV, Dobrush
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