Home

Dial a phone number to display the device circuit

The device and display features that do not have dial telephones in parallel, to display the allocation of telephone numbers in order to check the number dialed is correct.
Circuit as shown. Dial-up generated by dual tone multi-frequency (DTMF) signals from the DTMF *** CM8870P1 (IC1) decoding, resulting in numbers corresponding to the telephone number BCD, each digit of the BCD codes are latched in the corresponding latch, The circuit can display 10-digit phone number. The first digit lock there IC5A (1/2CD4508), the second number in the lock there IC5B, and so on. For the number "0", IC1 decoded output is "1010", equivalent to a decimal number "10", it can not be decoded 7-segment decoder and then displayed IC10, IC1's output termination so there is P1 ~ P3 and N1 constitute the logic circuit. The circuit is able to "1010" turned into "0000" and the numbers 1 through 9 in BCD code of the circuit is not changed.
IC2 (CD4017BE) control the latch latched BCD code, IC1 pin 15 of IC2 the output signal for the clock pulses, IC2 output of the 10 were receiving the latch the clock and clear inputs, such as IC2's output is a high, the corresponding latch will clear the front of the data, and prepare to save the new data. Under the action of the clock pulse, such as high output of IC2 the end of an in the moment of transition is low, the latch in the appropriate input data to be stored, IC2's output goes high next so that the next data latch is cleared and ready to store new data.
10 LTS543 share a common cathode 7-segment display decoder driver IC10, this simplifies the circuit and reduce costs. 3 due to latch CD4508 feet or 15 feet is active low, so in the IC3 of the latch output and 3 feet or 15 feet were added between the level inverter. IC4 (NE555) constitute a multi-harmonic oscillator, the oscillation frequency of about 10kHz, oscillating pulse trigger IC3 (CD4017BE), to 10 cycles followed by the output of the output high, transistor VT0 ~ VT9 cycle followed by conduction, if a latch the output of a BCD code data, the display will show the corresponding BCD code with the corresponding decimal number. IC5A the data displayed on the display device "DIS1" on, ICSB's data is displayed in "DIS2" on and so forth. The display is actually a flashing light, but the flicker frequency high, the enemy will not have the eye of light flashes.
Maximum of ten digits of the circuit, in accordance with need to reduce the display digits, for example, to display 7 digits to 15 feet should be reset IC2 end its 15 S6 connected to the output pin.

Free Electronic ProjectsElectronic hobby projects, Electronic circuit, Circuits, Hobby circuits, Digital circuits, digital e...Digital clock circuitOne , designed to 1 . familiar with the IC 's pin arrangement . 2 . to acquire all the chip logic fu...Intelligent IP phone dialer circuitIP phone calls to save welcomed by the users. However, IP telephony has changed the way people turn ...Telephone detector circuit using 555 CD4017 CD4518Produced using this phone detector circuit that can accurately determine and eliminate telephone rin...IPM drive and protection circuitp> Abstract: This paper introduces the basic operating characteristics of the IPM and the IPM...Long-range cordless telephone and ordinary telephone connection method circuitIn many remote villages, the erection of telephone lines is too difficult, so more use of long-dista...LM567 Universal tone decoder integrated circuit applications567 for the general tone decoder, when the input signal in the pass band to provide saturated transi...Power supply switching protection circuitAbstract: In order to switch to emergency power failure in the harsh environment and safe conditions...Inverter circuit board and maintenanceA common style car on the market the main indicators of inverter products Input voltage: DC 10V ~...Parallel phone call transfer device circuitMore than one telephone line extension parallel two really easy to use, but usually when the phone r...Electronic memory maintanance circuit for telephonesThe role of memory to maintain the circuit in the electronic telephone line status, to send code to ...Digital Call control and call transfer circuit for telephone extension lineThe same line phone and an extension is quite common. Small commercial transfer switches and a simpl...Quick Introduction to Voice Trilogy Integrated CircuitsBasics Young enthusiasts started his electronic technology, we might start with the most innovati...Telephone connected home with emergency calling feature for secutiry purposeAttached to the family on the telephone circuit described in this article shall constitute theft of ...Multi-function smart phone socket control circuit (a)I. Features The nearest control, remote query function, remote on / off function, remote c...Remote controlled Telephone pickup circuit for mulfi functionsathe remote control function to the office workers bring a lot of work and life easy . I have a func...Simple short circuit tester coilsUsing the 555 integrated timer. Add a small amount of external components, can be made simple and pr...Telephone communication circuits-2// Telephone circuit (1) Telephone circuit (2) Telephone circuit (3) Telephone circ...Novel anti-theft phone device circuitPhone theft in general play are "interfering" or "absorption", that is illegal a...Multi-function smart phone socket control circuit (b)Do you want anytime, anywhere can control some of your appliances You want to pull a phone call anyw...

Free Electronic projects & 8085 projects

Recent Projects

Dial a phone number to display the device circuit