[[http://www.tek.com/keithley-source-measure-units/keithley-smu-2400-series-sourcemeter|http://www.tek.com/keithley-source-measure-units/keithley-smu-2400-series-sourcemeter]]

Basically:

    * 220 LED series: $300
    * 2400 VFD series: $3000
    * 2500 touch series: $4000

Its unfortunate 2500 series hasn't driven 2400 series down

^Series ^Model ^V res ^I res ^MSRP ^Surplus low ^Notes |
|220 / LED |220 |  |500 fA |  |  \\ 850 \\  \\ Auction 61+ \\  |  |
|220 / LED |224 |  |  |  |480 |  |
|220 / LED |225 |  |  |  |  |Analog programmable |
|220 / LED |230 |  |  |  |280 |  |
|220 / LED |238 |  |  |  |855 |  |
|2400 / VFD |2401 |  |  |3590 |  |  |
|2400 / VFD |2400 |  |  |4900 |2800 |  |
|2400 / VFD |2400-LV |  |  |4900 |  |  |
|2400 / VFD |2400-C |  |  |6600 |5295 |  |
|2400 / VFD |2410 |  |  |7080 |4200 |  |
|2400 / VFD |2420 |  |  |7500 |3000 |  |
|2400 / VFD |2440 |  |  |8230 |6000 |  |
|2400 / VFD |2425 |  |  |8580 |2925 |  |
|2400 / VFD |2410-C |  |  |8670 |4200 |  |
|2400 / VFD |2420-C |  |  |8740 |3000 |  |
|2400 / VFD |2440-C |  |  |9840 |6000 |  |
|2400 / VFD |2425-C |  |  |10200 |2925 |  |
|2400 / VFD |2430 |  |  |12500 |8000 |  |
|2400 / VFD |2430-C |  |  |14300 |  |  |
|2450 / touchscreen |2450 |  |  |5400 |4750 |  |
|2450 / touchscreen |2460 |  |  |7500 |5500 |  |
|2450 / touchscreen |2461 |  |  |8500 |  |  |
|6220  |6220 |  |  |4050 |5000 |  |
|6220 |6221 |  |  |5390 |  |  |

Other current sources

    * Calex
      * Voltage programmable
    * LakeShore cyotronics
      * Voltage programmable
    * Optronic
    * Advantest TR6150
    * Advantest R6144: 100 uA steps

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