Pulse transformers

Because a pulse is not a DC voltage.

It's a pulse, a momentary change from low to high and then back to low.

Michael

Transformers produce a magnetic field when DC current is applied. Since transformers are inductive, the magnetic field builds as the inductor gets nearer to saturation. This building effect is producing a moving field, and the secondary of the transformer is with in this same field.

If you have ever taken a coil of wire attached to a volt meter and passed a magnet through it or passed the wire over the magnet, you'd noticed that the meter is giving you an indication that its generating electrical energy.

You can think of the transformer windings on the primary side as being the magnet and the secondary side as the coil of wire.. In this example, the magnetic field is moving because the wire in the primary side is an inductor. As time goes by after you initially applied the DC source on the primary side, current will start to build, the non instant building of current is generating this moving field I spoke of...

In your question of a pulse transformer.. The primary side is energized with DC for a short time. This initial signal applied to the primary side will not appear on the secondary side rite away because it needs to build current in the primary which generates the magnetic field you need.. Once the transformer becomes saturated, you'll no longer see output on the secondary side...

Example.. A square wave pulse of lets say 100 ms on the primary side, may generate a

Pulse transformers are designed to not saturate on the DC offset created by a train of pulses. Capacitance is often used to block the DC component of the train. The voltage output on the secondary side will have no DC component in the pulse train. This means that the average positive pulse value of voltage times time will exactly equal the negative pulse value. Depending on the pulse pattern the pulse height will wander up and down maintaining this condition. A DC restoring circuit, usually just a diode can clamp the output train to a fixed voltage, usually ground. Elementary my dear Watson!

I don't think that you are really Sherlock Holmes.

John

Yes, any transformer can pass digital pulses through, yet the shape of the pulses on secondary may not be the same in all transformers.

Pulse transformers are built to have better "square" pulses on secondary than other transformers

Whatelse ???

In other words, I'd like to say

Pulse transformers are built to have higher efficiency than others for pulses

;-)

No, they operate over a wider frequency range.