Position: Index > Phone Circuit >

Telephone account using a calculator and cob principle

2016-02-15 05:25  
Declaration:We aim to transmit more information by carrying articles . We will delete it soon, if we are involved in the problems of article content ,copyright or other problems.

This article describes a telephone account using a calculator and cob principle. In order to better grasp the principle of combining text, please understand this schematic. Before use, check its suitability by applying solid 1.5 v DC side between C and D, as shown. Then check the DC voltage terminals A and B; these terminals on a clock which is connected to a coil. If you stick in good condition, the multimeter needle will move forward and backward once per second. In fact, the 0.5 Hz clock in the terminal A and B, phase difference of 90 o. The advantage is that it works with this stick in a 1.5 v DC source.Clock pulses from the terminal A and B can be combined with a bridge, including diodes D1 to D4, get 1 Hz clock pulses. These clock pulses are applied to the base of transistor T1. The collector and emitter of transistor T1 is connected to the calculator '=' terminals. The formation of an equivalent number of pulses may be determined from the most recent call to the telephone directory. However, the pulse repetition frequency (PR) found in the directory can not be directly used in this circuit. Compatibility with this circuit, the pulse rate applicable to a specific place / distance, based on time of day / holiday into a pulse rate equivalent to (pre-) using the formula PRE = 1 / PR. You can prepare a variety of pulse rate look-up table and their equivalents (see Table). Suppose you want to make the call in pulse rate 4 STDs. From the table to write down the pulse rate, pulse rate is equivalent to 4, which is 0.25. Note that in the mature a telephone in a telephone exchange, a call immediately switched telephone account, it advances will further increase the pulse rate. Therefore, a call should be included in the calculation of calls. To make calls in pulse rate 4, slide switch S1 to 'off' (pulse setting position) and press the calculator button in the following order: 1, " ", 0.25, "=." Here, 1 is the most preliminary statistics, and 0.25 is PRE. Now the calculator display 1.025. Called meter is now ready to count. Call now, if called mature, immediately slide switch S1 '' (start / standby position). Corn begins to generate clock pulses of 1 Hz. Once per second transistor T1, so "=" button to activate the electronic calculator is once per second. Calculator display
Start from 1.25 per second advance is as follows:
1.25,1.5,1.75,2.00,2.25,2.50 so on.
After the call is completed, immediately slide switch S1 to the "off" position (pulse set position), and write down the local call meter reading from the calculator display. If a decimal value is greater than or equal to 0.9, add another call, the digital value. If a decimal value is less than 0.9, neglect decimal value and note only integers. To store this place called meter reading to the calculator memory, press the "M " button. Now local calls meter reading is stored in memory and added to the front of the place called the meter readings. For continuous displays current local call meter reading, press the "MRC" button and slide switches S1 '' (start / standby position). Current local call meter reading will blink once per second. In the prototype circuit, the authors used TAKSUN calculator, cost about 80 rupees. Shows a high 1 cm. In this calculator, he replaced two hooded cover batteries and two external connections 1.5 v R6 type batteries run more than one year calculator. Power "off" button is false cellotape paste in the contact terminal to avoid clear the memory, should someone accidentally press the power off button. This calculator has been automatically shut down the device. Therefore, some of the buttons need to keep on the calculator. "So, in the idle state," = "button is activated once per second by the electron transistors T1, keeping Calculator" constantly. Useful tips. Solders '=' button terminal through holes drilled around it in the  PCB  pattern thin copper wires and solder it with neat, so "=" button to activate the electronic and manual. The wire through the hole on the back of a printed circuit board, from where it left off the calculator as a terminal G and H. In the calculator battery terminals, solder two wires " " and "-" terminals. These wires also come from the calculator as a terminal E and f. Affixes stick a common PCB and solder the remaining components and tidy. To the unit an elegant look, buy jewelry plastic flip-lid box (size 15 cm x 15 cm). Now repairing boards, calculators, batteries, and caught in the jewelry box. Then mount the box on the wall inside the box look-up table attached to the cover in such a way, in the open box, which is displayed in the left box. Cautious. The negative side of the battery and the battery B must be kept isolated from each other the correct operation of the circuit. The principle is very practical, you can Duokanjibian better grasp this principle again.
 

LookUp Table
Pulse rate (PR)22.53468121624323648
Pulse rate eqlt. (PRE)0.50000.40000.3330.2500.1660.1250.0830.0620.0410.0310.0270.020
Note : Here PRE is shown up to three decimal places. In practice, one may use up to five or six decimal places.
Telephone call meter using calculator & COB

Telephone call meter using calculator & COB

VN:F [1.6.9_936]

 


Reprinted Url Of This Article:
http://circuits.radio-electronics.co/telephones/telephone-call-meter-using-calculator-cob/