Inverters and Buffers

Inverters and Buffers are digital electronic devices which have a single input and a single output. Inverters complement any input applied to them. In an inverter, a LOW input (0) produces a HIGH output (1) and a HIGH input produces a LOW output. To realize the operation and characteristics of inverters, a logic trainer, a volt-ohm milliammeter, a resistor and a TTL Hex inverter IC 7404 (with six identical and independent inverters) are used. Buffers allow the input signal to pass through without any change. Hence they are used whenever input signal has to isolate from the output signal. Foe LOW input, Buffer gives LOW output and for HIGH input, Buffer gives HIGH output. If two inverters are connected in cascade, the circuit acts like a Buffer or non-inverting amplifier. Input impedance is high and output impedance low for Buffers. IC7437 is an example for quad 2 input NAND buffer. Output current in IC 7437 is thirty times the input current.