PNP Transistor Switching Circuit . The concept of PNP transistor as a switch is that, the Current stops flow from collector to emitter only when a minimum voltage of 0.7V is supplied to the base ...

A previous Design Idea describes a circuit that uses an astable multivibrator to drive an LED (Reference 1). The circuit in Figure 1 uses a simpler alternative approach. The circuit uses a 2N3904 NPN ...

Simple 100mA Constant Current Source using Transistor. In this project, we will build a simple transistor constant current source generator using only 4 components. It is a very inexpensive circuit ...

Presented here is a simple circuit that will help you figure out whether a transistor is npn or pnp type. If the transistor under test is npn, red LED will blink. If it is pnp, green LED will blink.

A transistor tester can be a handy addition to your electronics workbench.This versatile transistor tester design, first presented a decade ago, enables you to quickly assess the functionality of ...

00 While experimenting with electronic circuits, it will often be necessary to rap- idly test bipolar transistors and FETs before they are fitted in the circuit, or when they have been removed from ...

This is simple circuit that illustrates the function of the programmable unijunction transistor. It may be quickly wired on a proto-board. The programmable unijunction transistor remains dormant until ...

In the early days, PNP bipolar transistors were common, but the bulk of circuits you see today use NPN transistors. As [Aaron Danner] points out, many people think PNP transistors are “backwa… ...