This particular timing circuit can be used to time one-shot events from a few seconds to a few hours. And in standby mode (ie, with RLY1 and LED1 off), its power consumption is very low. The heart of this circuit is a low-cost CMOS 4011 quad NAND gate, with....

Although the parts list calls for a ten-segment LED unit, the illustration shows two individual LEDs being used instead. This is due to lack of room on my breadboard to mount the switch assembly, two integrated circuits, and the bargraph. If you have room on....

This circuit uses just two CMOS IC`s, a 4011 quad 2 input NAND gate, and a 4020 14-stage ripple binary counter. At switch on R2 and C2 provide a brief reset pulse, which will ensure the output pin Q1 of the 4020 is high. Gates U1 and U2 form a simple astable....

Work of the circuit The circuit consists of low-frequency oscillator, the electronic switch circuit, control circuit, photoelectric display circuit and music alarm circuit. (It is showed in picture 7-113.) Low-frequency oscillator consists of IC lCl (Dl-D4)....

A TTL logic probe is an indispensable tool for digital circuit troubleshooting. Various methods can be used to design a logic probe. The most common designs employ opamps, logic (OR, NOT, XOR) gates, and transistors. The circuit presented here uses NAND....

As the figure 15-22 shows, the doorbell is composed of the monostable timing circuit, the password switch, the NAND gate circuit and the sound circuit.etc. In the limited time, the circuit uses the program to press the password switch, the doorbell circuit....

This circuit is composed of a temperature sensor, amplifier, V/F converter, three digit binary coded decimal (BCD) counter, time base and seven segment led displays. In addition to the 9400 V/F converter, other ICs need for this project include the LM334....

Two multivibrators with different frequencies can be built using the NAND gates of a 4011 IC. If the output of IC1. B is positive with respect to IC1. C, LED D1 is on. As the levels of IC1. A and IC1. D are exactly opposite, D2 is always on when D1 is off,....

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This circuit is very useful while checking/operating counters, stepping relays, etc. It avoids the procedure of setting a switch for the required number of pulses. By pressing appropriate switches S1 to S9, one can get 1 to 9 negative-going clock pulses,....

Figure 1 shows a circuit for sensing the water level in a tank and turning on or off a water pump accordingly. The main component of the circuit is the CD-4011 Quad NAND gate, three gates of which are used as shown in Figure 1 (gates G1, G2, and G3). G1 is....

It`s very simple circuit using DTMF decoder MT8870 (or CM8870). As shown in the circuit, u`ll receive an interrupt ( if NAND output is connected to INT of the microcontroller) whenever u receive a call or make a call and then u can use yr program to read the....

I don`t know why, but people like blinking lights. You see LED chasers everywhere, in TV shows (Knight Rider), movies, and store windows. This schematic is my version of a simple 10 LED chaser. There is no 555 timer used because at my local electronics store....

As systems grow smaller, it becomes increasingly attractive to replace mechanical potentiometers with electronic potentiometers, which are smaller and less expensive silicon equivalents. A common interface for such devices comprises a Chip-Select, Increment....

This frequency doubler uses one CMOS quad, two input NAND gate package type 4011. The frequency doubler proper consists of an inverter IC1B, two differentiating networks R1/C1, R2/C2 and NAND gate IC1A, IC1C and IC1D function as input and output buffers. In....

The watchdog circuit in Figure 1 uses a single NAND Schmitt-trigger IC. The circuit is more cost-effective than dedicated, commercially available watchdog ICs. The circuit generates an active-high reset signal upon power-up and remains in a low state as long....

The circuit uses two CMOS IC’s IC1 uses inverters connected as a Colpitts oscillator of 100KHz; the LC frequency determining elements being the search coil and parallel resonating capacitor. An 80 turn close wound 30swg 100mm diameter coil will fit inside....

The resulting timer circuit is made from a CD4060, includes an oscillator and a 14 stage binary counter, two CD4040's, which are 12 stage binary counters, a CD4012 Dual Nand gate and a CD4013 Dual D Latch. The CD4060 is connected to a 32768 Hz ECS 3X8....

A VCO (voltage-controlled oscillator) is an analog circuit, so you cannot find it in the libraries for the design of digital programmable chips. When you need such a circuit for synchronization or clock multiplication, you need to find a circuit that works....

The Sun-Up Alarm can be used to provide a audible alarm for when the sun comes up or it can be used in a dark area and detect when a light comes on. It can also be used to detect a light beam, headlights etc. The circuit works as follows. The phototransistor....

The circuit shown below is a basic latching circuit consisting of a quad 2-input NAND Gate IC. It is configured such that the flip flop circuit U1A and U1B has both its input held at logic "1". Pin 1 is held at logic "1" by the magnetic contact and pin 6 is....

The Sun - Up Alarm can be used to provide a audible alarm for when the sun comes up or it can be used in a dark area and detect when a light comes on. It can also be used to detect a light beam, headlights etc. The circuit works as follows. The....

This circuit will divide the frequency of a TTL compatible square wave signal by a factor from 0 to 999. The circuit comprises three decade counters IC1 to IC3 and a few NAND gates. The three 7490?s are cascaded and count is the input signal. When the....

The circuit presented this month is a basic configuration of the very versatile 4017 IC Chip. In the most common use of the IC, it will turn on 10 separate outputs sequentially. Typically, the circuit is used to turn on a LED for certain time cycle. In the....

Here's another daft yet interesting PIC12F675 idea I came up with. When I wanted to show someone how logic gates worked I could only find a NAND gate which wasn't very handy for demonstrating AND's OR's, NOR's and ExOR's. I also wanted to have a play with....

Here we have three choices, with which we can make electronic switches that use our touch or pressing (push button). We thus exploit the very big resistance of entry, that present the gates CMOS. In the fig.1 we have two gates NAND or NOR (IC1), connected as....

Using two gates from a CMOS 4011 NAND chip, a simple aquarewave oscillator can br made. Alternatively a CMOS 4001 chip can also be used, or a TTL equivalent. In this circuit the mark space ratio can also be independantly controlled by varying the value of....

With this circuit we can create a altered sound of siren. The oscillator IC1a-b is constituted by two gates NAND, oscillating in very low frequency. This oscillation drive the IC2, that is a electronic switch, which opens and closes in the rythm of....

IC1D is a CMOS Schmitt trigger oscillator at about 2KHz. It starts and continues to oscillate with a supply down to 1.24V (the lowest output voltage of my LM317 variable power supply) or less. IC1A is an inverter. IC1B is a Schmitt trigger NAND gate. Its....