TF EIM Chapt5

Half Wave rectifier

A half wave rectifier is a circuit which passes only half of the input AC waveform.

This is accomplished by using the diode's forward drop voltage to "clip" the AC signal.

Consider the following circuit

400 px

The Transformer

A transformer uses inductors/coils to step voltages either up or down based on the ratio of the number of coil turns[math]N_1[/math] and [math]N_2[/math].

Let [math]\Phi[/math] represent the magnetic flux seen by the inductors due to the changing current in the primary.

[math]V_{in} = N_1 \frac{d \Phi}{dt}[/math] = Input Voltage on the Primary side

[math]V_{out} = N_2 \frac{d \Phi}{dt} = V_{Finish} - V_{Start}[/math] = Output Voltage on the Secondary

The ground is relative for a transfer. You could use the "Tap" or center post as a ground and either the Start or Finish end

[math]V_{\mbox{out using Tap}} = N_{Tap \rightarrow Finish} \frac{d \Phi}{dt} = V_{Finish} - V_{Tap}[/math] = Output voltage between Tap and Secondary

Where [math]T_{Tap} =[/math] ground

Since both coils see the same flux

[math]\frac{d \Phi}{dt} = \frac{V_{in}}{N_1}= \frac{V_{out}}{N_2}[/math]

[math]\frac{V_{out}}{V_{in}}= \frac{N_2}{N_1}[/math]

If [math]N_2 \gt N_1[/math] you have a step UP (Voltage increasing) Transformer

If [math]N_2 \lt N_1[/math] you have a step DOWN (Voltage decreasing) Transformer