This design is to makes use of the appropriate chip of ICL7107 to design a 3 1/2 arithmetic digital electric voltage form, it adopts four figureses show, can measure direct current voltage between -20V~+20V ,and the number of the chips are small. Big electric current in adoption in ICL7107 anti output mutually, the constant drives the anode LED display totally, be provided by power supply of ±5V, show that the bright degree is high but consume the electricity bigger, be suitable for the small scaled set in manufacture type 3 1/2 arithmetic figures appearance.
Work process is as follows:After the electric voltage which wanted to be measured was pressed by dividing machine( resistance) proceeds to divide the reduces at the input of the electric circuit part ,it is sended to the A/ D conversion machine.Pass the A/ D conversion changes into the arithmetic figure signal, transporting to the arithmetic figure electric circuit.Then be given by arithmetic figure electric circuit LED arithmetic figure signal, control its give out light, from but manifestation arithmetic figure.
Key words:ICL7107;LED;The machine of clock oscillates RC;
An integral calculus type A/ D conversion machine