This is my first project on Easyeda. Still struggling to get it to be simulated. If anyone can see what I did wrong (I think it might have to do with my power sources) let me know! Basically, this is a circuit to convert a 0-267Hz signal into a 0-1.6Vdc output with a 200mA capability. The LM2907 transform the frequency into the voltage. The LM741 op amp take this voltage and trigger the BCW66G transistor. There is a feedback wire on the emitter side of BCW66G that let the op amp adjust it output voltage so that the Emitter voltage of the transistor is the same as the output voltage of the LM2907. L1 is a coil. In real life it is an electromagnet that provide the torque to move the tachometer needle against as return spring. Why can't it be simulated??