Small electronics circuitsLast modified: July 27, 2015

Attenuator

Introduction

What is it? What is it used for? How is it typically made? Pictures.

An attenuator takes a large electric signal in the form of a voltage and turns it into a smaller signal. This is sometimes also called a voltage divider, because the circuit divides the voltage into 2 parts and sends one part to the output.

An attenuator is useful in situations where you don't want a large signal. For instance, when you put an input into the audio jack of a computer.

Materials2 resistors

Can exchange one resistor for a variable resistor to make a variable attenuator

WiresSolder + solder wick(breadboard)

Can put it into a box with a few connectors (BNC, etc.)

ToolsWire strippersSoldering iron

Procedure

Circuit + equation

Characterization

Tips and tricks

Amplifier

Introduction

What is it? What is it used for? How is it typically made? Pictures.

An amplifier takes an electric signal in the form of a voltage and turns it into a larger signal. This is useful in situations where you need a larger signal, such as when you're trying to listen to a signal from your radio. Your ear can only pick up signals so small, so amplifying it will make it easier to hear. Materials4 resistors2 capacitors Wires Operational amplifier (Op Amp)9V battery for powering Op Amp (depends on how much voltage you want in the output)

ToolsWire strippersSoldering iron

Procedure

The two circuits below make up the amplifier. They are both built on the same op amp, but just separated into two pictures for clarity.

This circuit is a power supply for the op amp. The voltage of the battery is the maximum voltage of the amplified signal. This circuit also consists of 2 low-pass filters (?) for the operation amplifier. Each low-pass filter consists of a resistor and a capacitor. The filter is to protect the op amp from large noise peaks, which could destroy the fragile transistors and diodes that it's made out of.

This is the amplifying part of the circuit. The resistances are here just as an example. How it works is that the op amp wants to keep the two inputs (to + and -) at the same voltage and drawing zero current. In doing so, building this circuit means that the (-) input must have 0 volts and the same current goes through the 5 kOhm resistor as goes through the 50 kOhm resistor. Thus, the voltage drops to 0 across the 5kOhm resistor and then drops to minus 10 times the original voltage after the second resistor, leaving a final voltage that is minus 10 times the original.

Characterization

Tips and tricks