bi-fet op-amps

Interesting results can often be obtained by using several different types of active device in one circuit. Examples of this type/of `hybrid` circuit are designs incorporatingJSoth transistors and valves (or `tubes` Am. or `bottles` SI.) or TTL and CMOS, or bipolar transistors and F ETs. A relatively new example of this is the B1-FET opamp. It consists of J F ETs and bipolar tran- sistors on the same chip, and this r.ould well give interesting results at a reasonable price.