The CMOS TLC555 [equivalent to the bipolar 555] can be used as a monostable in the configuration shown here. The time the output remains high depends on FM and [31 based on the formula in the diagram. The minimum value recommended for R1 is 1 k ohm and for C1 is 100 pF, The highest value for these components depends on the losses in the capacitor and is typically 2.2 M ohm for R1 and 1500 µF for C1. The TLC555 can drive or source 200 mA in its output – directly driving relays and lamps. This circuit is triggered when the input [pin 2] is grounded. When waiting, pin 2 may be held at the high logic level. This can be done with a resistor between 10 k ohm and 1 M ohm. In the formula:

T is the period in seconds [s]

R1 is the resistance in Ω [0]

C is the capacitance in farads [F]


Basic Monostable Using the 7555 (CMOS)
Basic Monostable Using the 7555 (CMOS)


Datasheet of TLC555



N° of component