Figure 4-14 is a digital integrated circuit consisting of 16 preset potentiometers Siniperca electronic circuits. It consists of three parts: input into the controller. Presett
able counter, analog electronic switch and resistor network. Assisted by a push-button switch and the controller Schmitt trigger four two-input NAND gate CD4093 composition. By adding to the counter to control the input, counting down switching pulse counting and addition and subtraction states. Wherein ICIA, ICIB composition subtraction count the number of input NAND gate. Iclc.rq Hu lying grate RS flip-flop, whose output controls the down counting of the counter IC3 state transition when it outputs a high level, IC3 for counting; low output, IC3 for counting down. IC2E to the non-inverter, IC2F counting bit full control gate when the counter reaches the preset number or the full bit, IC3 output full bit (binary) signal IC2F closed to stop counting pulses input o can be preset count din. BCD can be preset by the reversible counting ICCDt029 preset number and BCD switch composition for receiving add, subtract and count pulse input preset number b When the count full bit full controller output to the input signal. Counter after receiving the count pulse t by adding, after the down output BCD code. U/D conversion is down counting state control terminal, a high level, the counter for counting; low, the counter for counting down port analog electronic switch and resistor network. By a single 16-channel analog switches CI, CD4067 16 and resistor networks.