An SCR topology transmogrifies into BJT two-wire precision current source with a self-resetting fault-current limiter.

The general-purpose current source in Figure 1 is accurate within 1% and insensitive to temperature (less than 50 ppm/°C). It also has a high output resistance and a wide compliance range (4.3 to 34..

An interesting analog design problem is the precision current source. Many good designs are available, but most are the three-wire types that can be used as a positive (see Figure 1) or a negative ...