exploreroots|T latch & circuit This latch is obtained from JK by connecting both the inputs. This is also known as Toggle latch as output is toggled if T=1. The truth table is: The circuit diagram of T latch is as follow: Simple Latch Circuit Diagram with Transistors Circuit Diagram: Circuit Diagram of Latching circuit is simple and can be easily built. Resistor R1 and R4 work as a current limiting resistor for Transistor Q1 and resistors R2 and R3 work as current limiting resistor for Transistor Q2. Current Limiting resistors must be used at the bases of BJT transistors, otherwise they might burn.