# How do I make voltage step on proteus?

I'm making this circuit on proteus but i don't know how to make this voltage step

Please tell me how to make voltage step on proteus.

## 1 Answer

I don't have Proteus but it should have one of two things in there:

1. A voltage source which can have specified a period T, pulse width Ton, rise and fall times tr and tf, lower and upper voltages V1 and V2, a delay Td, and an optional number of cycles N. With these you need to specify a pulse width of Ton=1 and a falling time of tr=1m (you can use 1u if you really want sharp times, but 1m should be enough and too low values may cause problems). Some SPICE simulators allow not specifying T, which means it goes indefinitely, but to be in the safe side set T to be greater than your total simulation time. E.g. if you plan to simulate for 10 sec then make T=11 (anything greater). Then make V1=10 and V2=0, while leaving tr=0 and Td=0 since they are not needed.
2. A PWL (Piece-Wise Linear) source, which can have pairs of value-time points. E.g. for your case you can set these to 0, 10, 1, 10, +1m 0. This says at time 0 the value is 10, then at time 1 the value is still 10, and at +1m compared to the previous time point (1) the value is 0. Just like above, you could have +1u if you really need very steep slopes, but I doubt you'll ned it.

Additionally, in SPICE there are also behavioural sources, and if Proteus has them then you can write the equivalent of if(time < 1, 10, 0).

To be on the safe side I'll add: don't forget to add a ground node, since everything needs to be referenced to it.

• thanks! i will try it Commented Jun 7, 2021 at 4:40