SN74LS221NG4

Logic - Multivibrators are devices that are used to generate short-duration, accurate asymmetrical square wave signals. They usually feature two distinct threshold levels, and when one of these thresholds is reached, the output switches states and a pulse form is generated.

The SN74LS221NG4 is an example Logic - Multivibrators device, featuring two Schmitt triggers with two independently adjustable threshold levels. The device is packaged in a small, 8-pin SPDIP, and provides a highly reliable pulse generator for AC or DC operation.

The SN74LS221NG4 application field includes timer circuits, communications systems, computer logic, ripple counters and logic circuits for driving display systems. Due to its adjustable threshold levels, the device can be used for generating specific types of pulse signals.

Working Principle

The SN74LS221NG4 Logic - Multivibrator generates a square wave signal, based on the voltage intervals at its inputs. Depending on the applied voltage, the output on either side of the logic circuit can switch states. When one input exceeds the specified threshold, output A will switch to logic 1, and similarly, when the other input exceeds its threshold, output B will switch to logic 0.

This will result in a pulse signal, with a width proportional to the difference in the applied threshold voltages. Both the duration and shape of the pulse can be adjusted, and as such, it is possible to generate almost any desired pulse shape (like low-frequency timing signals, for example).

In principle, the SN74LS221NG4 produces two separate output signals. The first signal is generated when the active-low input A exceeds its threshold, and the second signal is produced when the active-high input B falls below its threshold. It is also possible to obtain a pulse of varying duration by adjusting the two threshold levels.

In addition, by increasing the supply voltage, the output frequencies of the device can be increased as well. This is particularly useful for applications that require a higher output frequency than the standard configuration can provide.

The SN74LS221NG4 device is a great example of an asynchronous Logic - Multivibrator, providing reliable, accurate and predictable output signals. It has been designed to provide reliable operation in AC or DC power supplies. As such, it is a perfect choice for applications that require a low-cost, low-power pulse generator.