Circuit Project Description

The circuit was constructed to produce a **frequency divider** with the use of flip flops which are the basic building blocks of sequential logic circuits while forming a T flip-flop configuration.

Terminology**Toggle (T) Flip Flop** – a clocked flip-flop whose output changes or toggles to the complementary logic state on every transmission of the clock signal and functions as a divide-by-two counter since two active transitions of the clock generate one active transition of the output**4011 **– a quad 2-input NAND gate integrated circuit, generally characterized by small fluctuation in voltage supply, very high impedance, outputs that can sink and source, one output can drive up to 50 inputs, high speed gate propagation time, high frequency, and low power consumptionCircuit Explanation

A flip flop is a clocked device that can store 1 bit of information and can change its value only at positive clock edges. The flip flop maintains or holds its value in the absence of a positive edge. Compared to combinational logic circuits, the flip flops allow sequential logic circuits to have a state like the memory. In a T flip flop, the output is changed on each clock edge, giving an output which is half the frequency of the signal to the T input. The T flip flop is useful for constructing frequency dividers, binary counters, and general binary addition devices. One great thing about T flip flop is that it can be built using a JK flip flop or a D flip flop.

The circuit forms the T flip flop arrangement using IC1 4011. During the operation, the network frequency is limited to the negative half cycle of the sine wave. This is then transformed into a square wave and gets divided by two. This can be illustrated from an input frequency of 50 Hz and half of it will be taken resulting to an output pulse of frequency of 25 Hz. The circuit is being supplied by a 5 V source and will not require a high amount of current consumption. A transformer can be used that can provide up to 8 V but will be limited to 5 V due to the presence of Zener diode D3.

Part List

R1= 10Kohm R2= 100Kohm R3= 680 ohm R4= 1Mohm R5-6-7= 100Kohm |
R8= 47 ohm R9-10-11= 100Kohm C1= 1000uF 25V C2-3= 100nF 100V ceramic C4-5= 100pF ceramic |
IC1= 4011 T1= 110/220Vac //8V 100mA D1-2= 1N4007 D3= 5.1V 0.5W Zener D4-5= 1N4148 |

Application

The frequency divider using T flip flops are being applied in A/D converters, Time-to-Digital converters, digital correlators, ripple counters, and television designing & construction. Some designs may be used in today’s RFIC, microwave circuits and other industrial applications since it is an integral part of the phase locked loop (PLL) circuit.