Logic gatesΒΆ

Logic gate circuits can perform operations like AND, OR etc. They can be implemented using PN junction diodes for demonstration purpose. A wide range of logic gate ICs are also available.

Objective

Study of logic gates using SQ1 and PV1 as inputs, using TTL logic ICs 7408 and 7432.

Procedure

_images/gate-or-diode.svg _images/gate-and-ic.svg
  • On a bread board, wire one of the circuits shown above.
  • Enable A1, A2 ands A3. Set input range on A1 and A2 to 16V
  • Set SQ1 to 500 Hz and WG to 1000 Hz
  • Select SQ2 from the WG wave shape
  • Shift the traces using the vertical sliders on the left, for better view.

The results for the OR gate made using the diodes is shown below.

_images/gate-or-diode-screen.png

The results for the AND gate made using the IC 7408 is shown below.

_images/gate-and-ic-screen.png

Discussion

The working of the logic gate will be evident from the 3 waveforms. You may shift traces vertically to separate them for clarity.