Think of Texas Instruments" SN54121J monostable multivibrator the next time you need to be alerted when a chosen condition is met within your project. This monostable multivibrator has an operating temperature range of -55 °C to 125 °C. This device comes in tube packaging. This device has a typical operating supply voltage of 5 V. Its minimum operating supply voltage of 4.5 V, while its maximum is 5.5 V.