Peter Johns together with his postgraduate student, Mark O’Brien first suggested the use of TLM to model reactive components in electrical circuits (The Radio and Electrical Engineer **50** (1980) 59 – 70). This was based on the use of transmission line stubs, where an open-circuit stub behaves like a capacitor at frequencies which are low compared to the inverse of the sampling time. Similarly, a short-circuit stub behaves like an inductor for the same conditions. Some examples of the application of these ideas can be seen in TLM modelling of historical problems. Here are two examples of the Matlab code which is used in circuit applications.

The first is the use of TLM to simulate an ingenious circuit for a DC-DC up/down converter which is known as the Cuk converter. This simulation was developed by an undergraduate computing student as part of a coursework assignment in Power Electronics.

The second piece of code simulates a circuit which acts as a constant current source