Field Effect Transistor Circuits

A sine wave to triangle wave converter circuit including a first field effect transistor, a second field effect transistor, a third field effect transistor, and fourth field effect transistor wherein each of the first, second, third, and fourth field effect transistors include a drain terminal, a gate terminal, and source terminal comprising:

• a sinusoidal signal source coupled the gate terminals of the first and third field effect transistors;
• coupling to a first voltage potential the gate terminals of the second and fourth field transistors;
• coupling the drain terminals of the first field effect transistor to the second field effect transistor;
• coupling the drain terminals of the third field transistor to the fourth field effect transistor;
• coupling the source terminals of the first field effect transistor to the fourth field effect transistor;
• coupling the source terminals of the second field transistor to the third field effect transistor;
• coupling a first current source to the source terminals of the first field effect transistor and to the fourth field effect transistor;
• coupling a second current source to the source terminals of the second field effect transistor and to the third field effect transistor;
• providing a first output current terminal coupled to the drain terminals of the first and second field effect transistors;
• setting the current of the first current source not equal to the current of the second current source;
• providing a triangle waveform current at the first output current terminal with the sinusoidal signal source.

A bias servo circuit to provide substantially equal resistance between two or more field effect transistors with each field effect transistor having a drain terminal, a gate terminal, and a source terminal, wherein the equal resistance between the two or more field effect transistors include the resistance between the drain terminal and source terminal of each of the field effect transistors comprising:

• the two more field effect transistors are substantially identical wherein the two or more field effect transistors includes a reference field effect transistor and a second field effect transistor;
• a reference voltage source that includes a direct current voltage;
• coupling the reference voltage source via a load resistor to the drain terminal of the reference field effect transistor;
• coupling the drain of the reference field effect transistor to a (+) input terminal of an amplifier;
• coupling the reference voltage source to a (−) input terminal of the amplifier;
• coupling an output terminal of the amplifier to the gate terminal of the reference field effect transistor;
• coupling the output terminal of the amplifier to the gate terminal of the second field effect transistor;
• wherein the resistance between drain terminal and source terminal of the reference field effect transistor is substantially equal in resistor between the drain terminal and source terminal of the second transistor.