Sick of building simple transistor circuits to find they fail. So I designed and built this test bed for small signal transistors. You work out the biasing resistor values then using a multimeter setup them up using the trim potentiometers. Connect power, an input signal and test equipment using the various pins. The board is primarily aimed at Common Emitter or Common Collector circuits, but other circuit configuations can be simulated too.

If the biasing isn't quite right you change it to suit your needs. Unplug everything including the transistor and measure the values.

By using a small 6 pin IC socket you can easily change transistors. The sockets are set to cover most of the transistor configurations by using one side of the socket or the other. A bypass capacitor can be switched if required. The 200 Ohm resistors are to stop the Base Bias values from going to zero.

10 boards for $5 from PCBway means you can have several built to quickly check different from small signal, Darlington, JFETs or MOSFETs.

N.B. this image is from a slightly earlier version. The published version has slightly different labels to reduce clutter.