Timing control circuit (2)

(1) Introduction to circuit principle This timing controller has time display, cycle timing, single timing and manual control functions. The timing time is 1-90min
. It can be used to control various electrical equipment that requires regular or intermittent work.
    The timing controller circuit is composed of a power supply circuit, a clock signal generator, a counting distributor, an RS flip-flop and a switch output circuit.
    The power circuit is composed of power transformer T, bridge rectifier uc, filter capacitors c1, cI, current limiting resistor Rs and voltage stabilizing diode vS.
    The clock signal generator consists of an electronic meter, diode VD1, capacitor C2 and counter/distributor integrated circuit IC 1.
    The counting distributor circuit is composed of the counting/distributor integrated circuit IC2, resistors R, , ken, timing selector switches Sl, S2 and reset button S4
.
    The RS flip-flop is composed of NOR gate integrated circuit IC3 (D1~D4), capacitors C3, C4, resistors, R, close button S5, open button
S6 and cycle/single timing conversion opening S3.
    The switch output circuit is composed of electronic switch integrated circuit IC4, diode VD2, relay K, light-emitting diode LED and resistor wind.
    The AC 220V voltage is stepped down by T, rectified by uc, and filtered by G to generate a 12V DC voltage. One channel is directly supplied to IC4#, and the other channel is subjected to
Rs current limiting and vs voltage stabilization, and Ci filtering to generate a 3V DC voltage, which is supplied to IC1~1C3.
    The Imin clock signal output by the liquid crystal electronic watch is used as the timing counting pulse of 1C2, and the fixed
time of 1-9min is obtained at its output end. If you need to expand the timing range, set Sl to the "×10" position. At this time, the 1rnin clock signal output by the electronic watch is advanced to IC1 for
counting distribution processing, and the obtained Omui clock signal is used as the counting pulse of 1C2. IC2 will Output the timing time of 10-90nun.
    After setting the scheduled working time selection switch S2 to the 5min timing position and S1 to the "×1" position, press the reset button S4 to
clear and reset IC1 and 1C2; the YO terminals of IC1 and 1C2 output high level, causing RS The flip-flop flips to Dl outputting low level, D2 and D3 outputting high level, and
the electronic switch inside IC4 is turned on. K is energized and closed, and its normally open contact connects the working power of the load (electrical equipment). At the same time, the LED lights up, indicating
that the load is powered on.
    When the timing time (Smin) arrives, the Y5 terminal of IC2 outputs a high level, causing the RS flip-flop to flip to Dl and D4 to output a high level, D2
and D3 output a low level, K is released, and its normally open contact opens the load The working power supply is cut off. At the same time the LED goes out. At this time, if S3 is placed in the "single
timing" position, the timing time will expire. 1C2 stops counting; if S3 is placed in the "loop" position, IC2 continues to count. After 5 minutes, its YO terminal
outputs a high level again, causing the RS flip-flop to flip, K re-energizes, the load is powered on, and the timing time (5nun) is reached Afterwards, the Y5 terminal of IC
,2 outputs high level, and the RS flip-flop fork flips... In this cycle, the load is energized intermittently,
    and Sl is placed in the "×10" position. When S2 is placed in the 5min timing gear, the timing time is 50min.
    When Sl is placed in the "stop" position, the cycle timing controller becomes manual control, and the status of the RS trigger can be directly controlled through buttons s5 and S6
to control the work or stop of the load.