Logic chip. Consists of four logical elements 2I-NOT. Each of these elements includes four field-effect transistors, two n-channel - VT1 and VT2, two p-channel - VT3 and VT4. Two inputs A and B can have four combinations of input signals. Schematic diagram and the truth table of one element of the microcircuit shown below.

Logic of operation of K561LA7

Let's consider the logic of operation of a microcircuit element . If voltage is applied to both inputs of the element high level, then transistors VT1 and VT2 will be in the open state, and VT3 and VT4 will be in the closed state. Thus, the Q output will be low. If a low level voltage is applied to any of the inputs, then one of the transistors VT1, VT2 will be closed, and one of VT3, VT4 will be open. This will set a high level voltage at output Q. The same result, naturally, will occur if a low level voltage is applied to both inputs of the K561LA7 microcircuit. The motto of the AND-NOT logical element is that zero at any input gives one at the output.

Truth table of the K561LA7 microcircuit

Pinout of the K561LA7 chip

A schematic diagram of a simple homemade photo relay on a K561 series microcircuit is given. The photo relay is designed to turn on the lighting at nightfall and turn it off at dawn. The phototransistor FT1 serves as a natural light level sensor.

Current is supplied to the lamp through a switching stage using high-voltage field-effect switching transistors, which operate similarly to a mechanical switch. Therefore, the lamp can be based either on an incandescent lamp or on the basis of any energy saving lamp(LED, fluorescent). The only limitation is that the lamp power should not be more than 200W.

Photo relay circuit

In the initial state, when it is dark, capacitor C1 is charged. The output of element D1.3 is one. It opens field-effect transistors VT2 and VTZ, and through them an alternating voltage of 220V is supplied to the lamp H1. Resistor R5 limits the charging current of the gate capacitance of field-effect transistors.

Rice. 1. Schematic diagram of a homemade photo relay on the K561LA7 microcircuit.

When light, the emitter-collector resistance of phototransistor FT1 decreases (it opens). The voltage at the D1.1 inputs connected together is equal to logical zero. The output D1.1 is one.

Transistor VT1 opens and discharges capacitor C1 through resistor R3, which limits the discharge current of C1. The voltage at the D1.2 inputs connected together drops to logical zero. A logical zero appears at output D1.2. Transistors VTZ and VT2 are closed, so no voltage is supplied to the lamp.

After the next decrease in illumination, the emitter-collector resistance FT1 increases (the phototransistor closes). Through R1, a logic one voltage is supplied to the inputs of element D1.1 connected together. The output D1.1 is zero, so transistor VT1 closes.

Now capacitor C1 begins to slowly charge through R4. After some time (1.5-2 minutes), the voltage on it reaches logical unity. At output D1.3, the voltage increases to logical one. Transistors VT2 and VTZ open and the lamp turns on.

Due to the time delay caused by charging capacitor C1 through R4, the circuit does not respond to a sharp and short-term increase in illumination, which can occur, for example, from the influence of the headlights of a car passing in the visibility zone of FT1.

The logic circuit is powered by a source based on diode VD4 and parametric stabilizer VD1-R6. Capacitor C2 smoothes out ripples. The most dangerous element in the circuit is resistor R6.

It drops significant voltage and power. When installing, it is advisable not to cut off its leads, but to bend and install the resistor so that its body is above the board and above the entire installation. That is, so that there are no conditions for breakdown to other parts through dust or humidity.

Parts and PCB

When the power consumption of the lamp is no more than 200W, transistors VT2 and VTZ do not need any radiators. You can also work with a lamp with a power of up to 2000W, but with appropriate radiators for these transistors.

The circuit is assembled on a miniature printed circuit board shown in the figure.

Rice. 2. Printed circuit board for a homemade photo relay circuit.

Instead of the L-51P3C phototransistor, you can use another phototransistor, as well as a photoresistor or photodiode in reverse connection (anode instead of emitter, cathode instead of collector).

In any case, the resistance R1 must be selected so that the circuit operates reliably (in the case of a photodiode, the resistance R1 will have to be significantly increased, and with a photoresistor, its resistance will depend on the nominal resistance of the photoresistor).

• Microcircuit D1 - K561LE5 or K561LA7, as well as K176LE5, K176LA7 or imported analogs such as CD4001, CD4011.
• Transistor KT3102 - any similar one.
• IRF840 transistors can be replaced with BUZ90 or other analogues, as well as with domestic KP707B - G.
• The KS212Zh zener diode can be replaced with any 10-12V zener diode.
• Diodes 1N4148 can be replaced with any KD522, KD521. Rectifier diode
• 1N4004 can be replaced with 1N4007 or KD209.
• All capacitors must have a voltage of at least 12V.

Setting up

The entire setup of the photo relay circuit comes down to setting up the photosensor by selecting resistance R1. If you want or need to change the setting quickly, this resistor can be replaced with a variable one.

The spatial installation of the photo relay and lamp plays an important role. It is necessary to ensure that the photo relay, namely the photo transistor, is located out of direct light from the lamp. For example, if the lamp is located under an opaque canopy, then FT 1 should be somewhere above this canopy.

Let's look at the circuits of four electronic devices built on the K561LA7 (K176LA7) microcircuit. The schematic diagram of the first device is shown in Figure 1. This is a flashing light. The microcircuit generates pulses that arrive at the base of transistor VT1 and at those moments when a voltage of a single logical level is supplied to its base (through resistor R2), it opens and turns on the incandescent lamp, and at those moments when the voltage at pin 11 of the microcircuit is equal to zero level the lamp goes out.

A graph illustrating the voltage at pin 11 of the microcircuit is shown in Figure 1A.

Fig.1A
The microcircuit contains four logical elements "2AND-NOT", the inputs of which are connected together. The result is four inverters (“NOT”. The first two D1.1 and D1.2 contain a multivibrator that produces pulses (at pin 4), the shape of which is shown in Figure 1A. The frequency of these pulses depends on the parameters of the circuit consisting of capacitor C1 and resistor R1. Approximately (without taking into account the parameters of the microcircuit), this frequency can be calculated using the formula F = 1/(CxR).

The operation of such a multivibrator can be explained as follows: when the output D1.1 is one, the output D1.2 is zero, this leads to the fact that capacitor C1 begins to charge through R1, and the input of element D1.1 monitors the voltage on C1. And as soon as this voltage reaches the level of logical one, the circuit seems to be turned over, now the output D1.1 will be zero, and the output D1.2 will be one.

Now the capacitor will begin to discharge through the resistor, and input D1.1 will monitor this process, and as soon as the voltage on it becomes equal to logical zero, the circuit will turn over again. As a result, the level at output D1.2 will be pulses, and at output D1.1 there will also be pulses, but in antiphase to the pulses at output D1.2 (Figure 1A).

A power amplifier is made on elements D1.3 and D1.4, which, in principle, can be dispensed with.

In this diagram, you can use parts of a wide variety of denominations; the limits within which the parameters of the parts must fit are marked on the diagram. For example, R1 can have a resistance from 470 kOhm to 910 kOhm, capacitor C1 can have a capacitance from 0.22 μF to 1.5 μF, resistor R2 - from 2 kOhm to 3 kOhm, and the ratings of parts on other circuits are signed in the same way.

Fig.1B
The incandescent lamp is from a flashlight, and the battery is either a 4.5V flat battery or a 9V Krona battery, but it is better if you take two “flat” ones connected in series. The pinout (pin location) of the KT815 transistor is shown in Figure 1B.

The second device is a time relay, a timer with an audible alarm for the end of the set time period (Figure 2). It is based on a multivibrator, the frequency of which is greatly increased compared to the previous design, due to a decrease in the capacitance of the capacitor. The multivibrator is made on elements D1.2 and D1.3. Resistor R2 is the same as R1 in the circuit in Figure 1, and the capacitor (in this case C2) has a significantly lower capacitance, in the range of 1500-3300 pF.

As a result, the pulses at the output of such a multivibrator (pin 4) have an audio frequency. These pulses are sent to an amplifier assembled on element D1.4 and to a piezoelectric sound emitter, which produces a high or medium tone sound when the multivibrator is operating. The sound emitter is a piezoceramic buzzer, for example from a handset telephone ringing. If it has three pins, you need to solder any two of them, and then experimentally select two of the three, when connected, the sound volume is maximum.

Fig.2

The multivibrator works only when there is a one at pin 2 of D1.2; if it is zero, the multivibrator does not generate. This happens because element D1.2 is a “2AND-NOT” element, which, as is known, differs in that if a zero is applied to its one input, then its output will be one, regardless of what happens at its second input .

A device for creating the effect of lights running from the center to the edges of the sun. Number of LEDs - 18 pcs. Upit.= 3...12V.

To adjust the flicker frequency, change the values ​​of resistors R1, R2, R3 or capacitors C1, C2, C3. For example, doubling R1, R2, R3 (20k) will reduce the frequency by half. When replacing capacitors C1, C2, C3, increase the capacitance (22 µF). It is possible to replace K561LA7 with K561LE5 or with a complete foreign analogue of CD4011. The values ​​of resistors R7, R8, R9 depend on the supply voltage and the LEDs used. With a resistance of 51 Ohms and a supply voltage of 9V, the current through the LEDs will be slightly less than 20mA. If you need the efficiency of the device and you use bright LEDs at low current, then the resistance of the resistors can be significantly increased (up to 200 Ohms and even more).

Even better, when using a 9V power supply, use serial connection LEDs:

Below are the pictures printed circuit boards two options: sun and mill:

Figure 2 shows a diagram of a simple time relay with LED indication. Time counting begins at the moment the power is turned on by switch S1. At the very beginning, capacitor C1 is discharged and the voltage on it is low (like a logical zero). Therefore, the output D1.1 will be one, and the output D1.2 will be zero. LED HL2 will be lit, but LED HL1 will not be lit. This will continue until C1 is charged through resistors R3 and R5 to a voltage that element D1.1 understands as a logical one. At this moment, a zero appears at the output of D1.1, and a one appears at the output of D1.2.

Button S2 is used to restart the time relay (when you press it, it closes C1 and discharges it, and when you release it, charging C1 starts again). Thus, the countdown begins from the moment the power is turned on or from the moment the S2 button is pressed and released. LED HL2 indicates that the countdown is in progress, and LED HL1 indicates that the countdown has completed. And the time itself can be set variable resistor R3.

You can put a handle with a pointer and a scale on the shaft of resistor R3, on which you can sign the time values, measuring them with a stopwatch. With the resistances of resistors R3 and R4 and capacitance C1 as in the diagram, you can set shutter speeds from several seconds to a minute and a little longer.

The circuit in Figure 2 uses only two IC elements, but it contains two more. Using them, you can make it so that the time relay will sound a sound signal at the end of the delay.

Figure 3 shows a diagram of a time relay with sound. A multivibrator is made on elements D1 3 and D1.4, which generates pulses with a frequency of about 1000 Hz. This frequency depends on resistance R5 and capacitor C2. A piezoelectric “tweeter” is connected between the input and output of element D1.4, for example, from electronic watch or handset, multimeter. When the multivibrator is working it beeps.

You can control the multivibrator by changing the logic level at pin 12 of D1.4. When there is zero here, the multivibrator does not work, and the “beeper” B1 is silent. When one. - B1 beeps. This pin (12) is connected to the output of element D1.2. Therefore, the “beeper” beeps when HL2 goes out, that is, the sound alarm turns on immediately after the time relay has completed its time interval.

If you don’t have a piezoelectric “tweeter”, instead of it you can take, for example, a microspeaker from an old receiver or headphones or telephone. But it must be connected through a transistor amplifier (Fig. 4), otherwise the microcircuit can be damaged.

However, if we don’t need LED indication, we can again get by with only two elements. Figure 5 shows a diagram of a time relay that only has an audible alarm. While capacitor C1 is discharged, the multivibrator is blocked by logical zero and the beeper is silent. And as soon as C1 is charged to the voltage of a logical unit, the multivibrator will start working, and B1 will beep. Figure 6 is a diagram of a sound alarm that produces intermittent sound signals. Moreover, the sound tone and interruption frequency can be adjusted. It can be used, for example, as a small siren or apartment bell.

A multivibrator is made on elements D1 3 and D1.4. generating audio frequency pulses, which are sent through an amplifier on transistor VT5 to speaker B1. The tone of the sound depends on the frequency of these pulses, and their frequency can be adjusted by variable resistor R4.

To interrupt the sound, a second multivibrator is used on elements D1.1 and D1.2. It produces pulses of significantly lower frequency. These pulses arrive at pin 12 D1 3. When the logical zero here, the multivibrator D1.3-D1.4 is turned off, the speaker is silent, and when it is one, a sound is heard. This produces an intermittent sound, the tone of which can be adjusted by resistor R4, and the interruption frequency by R2. The sound volume largely depends on the speaker. And the speaker can be almost anything (for example, a speaker from a radio, telephone, radio receiver, or even acoustic system from the music center).

Based on this siren you can make burglar alarm, which will turn on every time someone opens the door to your room (Fig. 7).