Capacitor charge and discharge periods is usually calculated through an RC constant called tau, expressed as the product of R and C, where C is the capacitance and R is the resistance parameter that may be in series or parallel with the capacitor C. It may be expressed as shown below: τ = R C […]
Newly Updated Circuit Projects:
UP DOWN Logic Sequence Controller Circuit
Using a set of latch/reset networks it becomes possible to allow a logic to move in a forward sequence, switching ON a given set of outputs HIGH, in response to an alternating input clock. And once the max limit is reached, the input clocks begin shutting down or withdrawing the sequence in the opposite order. […]
Common Emitter Amplifier – Characteristics, Biasing, Solved Examples
This configuration is known as common-emitter configuration because here the emitter is used as the common negative terminal for the input base signal and the output load. In other words, the emitter terminal becomes the reference terminal to both the input and output stages (meaning common to both the base and collector terminals). Common emitter […]
What is beta (β) in BJTs
In bipolar junction transistors the factor that determines the sensitivity level of the device to base current, and the amplification level at its collector is called beta or the hFE. This also determines the gain of the device. In other words, if the BJT uses relatively higher current to switch its collector load optimally then […]
Voltage-Divider Bias in BJT Circuits – More Stability without beta Factor
Biasing the terminals of a bipolar transistor using a calculated resistive divider network for ensuring an optimal performance and switching response is called voltage divider biasing. In the previous bias designs that I have explained the bias current ICQ and voltage VCEQ were a function of the current gain (β) of the BJT. But, as we […]
Darlington Transistor Calculations
Darlington transistor is a well known and popular connection using a pair of bipolar transistor junction transistor (BJT), designed for operating like an unified “superbeta” transistor. The following diagram shows the details of the connection. Definition A Darlington transistor can be defined as a connection between two BJTs that allows them to form a single […]