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In "small signal AC" analysis, you assume that the amplitude of the AC signal is negligibly small compared to the DC bias current. Therefore the AC signal doesn't significantly perturb the DC bias poi …

This may work well in simulation, but not quite as well in practice. Different NPNs will have different VBE for a given current and so their currents may not match. The switch that grounds the emitter …

The definition of saturation is VBC > 0. Thus VCE is less than VBE. Under normal conditions, VBE is around 0.7 V, and the transistor will operate reasonably predictability until VBC is over 0.3 or 0 …

If you care about leakage currents, and perhaps the switching speed of the circuit, I would suggest adding pull-down resistors between the base and emitters of each of the 4 H-Bridge transistors. Anyt …

You typically bias a transistor to optimize some conflicting, variable, and perhaps unclear goals: 1: To minimize wasted power (current) 2: To allow the AC component of a signal (added to the DC bias …

That PNP is biased off. I suspect you really intended to put an NPN there, and exchange the E & C ?

This circuit might work in a 'DC' mode; however it will not work well (or at all) in practice because of AC (loop gain) stability. Note that this circuit is not particularly precise -- the clamping po …

There is no 'VBE' parameter in a SPICE model. This is indirectly controlled via the 'IS' parameter. Be aware that a BJR doesn't just "turn on" at a single VBE voltage -- it's all gradual even from VBE …

There are two different effects on collector current that happen when VCE is increased. Which one depends on whether the VBE is held constant, or the IB is held constant. Base current is the sum of B …

Yes, you can exchange emitter and collector, but the transistor won't work as well. Generally the emitter is doped much higher than the base, and base is doped higher than the collector. This improves …

A BJT has a very definite relationship between VBE and currents. MOSFETs have lower gm (dI_drain/dVGS) which is not as precise as BJTs. … The current that flows in your R_GS is linear with VGS; a BJT is exponential. There is no definite relationship (like beta) between resistor current and drain current. …

Depending on the MCU, its IO pin may be tri-state at power up (or reset) until it is programmed to either a '0' or a '1'. If it is tri-state, small amounts of leakage (on the transistor, pin, or PC bo …

You are correct. Unless the transistor is in saturation, IC is nearly equal to IE. Therefore (nearly) the same current flows in RC and RE. So for a change in the base voltage deltaVB, a change in emit …

The B-E diode (even if connected with B-C shorted) will generally have a breakdown voltage of about 6 V, and likely if you apply lower reverse voltage for more than a few hours you may find that the t …

While beta is useful To broadly describe BJT performance, it is not a fundamental parameter of the device. …