Welcome to Richard’s Electronics Lab

Join me on my goal to learn and enjoy the pastime of hobbyist electronics, from starting electronics to discovering and using components to learning how why and when to use them in electronic circuits.

I will also be discussing and using electronic testing equipment to better understand how this equipment helps us accomplish certain tasks in electronics.

Please check out my videos and please leave a comment to correct any mistakes or incorrect assumptions I make so we can all learn and benefit from the community

Ask questions and provide comments using the Community Forum

Diode Clipping Circuit

Diode Clipping Circuit

Diode Clipping Circuit for Hobbyist Electronics

In this video we will take a look at a diode clipping circuit. This circuit comprising of a diode and resistor can can be considered a wave shaping circuit that takes an input waveform and clips or cuts off its top half, bottom half or both halves together.

Diode Clipping Circuit

Diode Clipping Circuit

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Peak Detector Circuit

Schmitt Trigger

Schmitt Trigger Circuit

Taking a look at a Schmitt Trigger circuit for Hobbyist Electronics

In this video we will be taking a high level look at a Schmitt Trigger circuit. This circuit is useful as it can convert any regular or irregular shaped input waveform into a square wave output voltage or pulse.

Demonstrating this circuit on the bench using a Function Generator for input signals and an Oscilloscope for output signal analysis.

schmitt-trigger

Schmitt Trigger Circuit with labelled components

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Voltage Follower Circuit

RC Phase Shift Oscillator

RC Phase Shift Oscillator

Taking a look at the RC Phase Shift Oscillator for Hobbyist Electronics

In this video we will take a high level look at the RC Phase Shift Oscillator and demonstrate the working circuit on an oscilloscope.

This RC Phase Shift Oscillator is using an op amp LM741 and a 3 stage phase network.

Links to useful online resources for this circuit can be located here: http://www.electronics-tutorials.ws/oscillator/rc_oscillator.html and https://en.wikipedia.org/wiki/Phase-shift_oscillator

LM741CN datasheet can be found here: http://www.ti.com/lit/ds/symlink/lm741.pdf

RC Phase Shift Oscillator

RC Phase Shift Oscillator

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Transistor Relaxation Oscillator

Voltage Follower

Voltage Follower Circuit

Taking a look at the Voltage Follower Circuit for Hobbyist Electronics

In this video we will take a look at the way a voltage follower circuit works. The voltage follower using an LM741 Op amp in this circuit provides a gain equal to 1 to maintain the input voltage on the output but offers high input impedance to prevent loading the voltage divider and affecting the expected required voltage

http://www.ti.com/lit/ds/symlink/lm741.pdf

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Transistor Latch Circuit

Darlington Transistor

Demonstrating a Darlington Transistor

Demonstrating a Darlington Transistor for Hobbyist Electronics

In this video we will demonstrate the operation of a Darlington Transistor. Using a DC Electronic Load we will apply various loads to the a single transistor and then two transistors configured as a Darlington Pair to demonstrate the increase in gain.

Darlington Transistor Circuit

Darlington Transistor Circuit

S9018 Transistor Datasheet http://vakits.com/sites/default/files/S9018%20Transistor.pdf

Useful article on the Darlington Transistor http://www.electronics-tutorials.ws/transistor/darlington-transistor.html

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Transistor as a Switch

RL Filter Circuit

RL High/Low Pass Filter Circuit

RL High/Low Pass Filter Circuit Demonstration for Hobbyist Electronics

In this video we will take a look at RL High, Low pass filter circuits. This will be a high-level demonstration using a Function Generator and Oscilloscope to examine the filters under test. We will also use an LCR meter to measure the inductors inductance.

We will first demo the High Pass Filter and then look at the Low Pass Filter using a range of frequencies above and below the cut off frequency of 91 kHz based on the selected resistor (27 ohms) and inductor (47 uH)

Cut-off Frequency Formula for an RL filter: ƒc = R/(2πRL)

Website link to RL Filter Calculator: http://www.learningaboutelectronics.com/Articles/Low-pass-filter-calculator.php

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Arduino GSM Modem Shield

RC Low/High Pass Filter Circuit

DC Voltage Boost Circuit

Inductor in a DC Voltage Boost Circuit

Taking a look at an Inductor in a DC Voltage Boost Circuit for Hobby Electronics

In this video we will examine a circuit utilising an inductor. This circuit is a DC voltage boost circuit example and i will attempt to demonstrate the circuit on the bench using an Oscilloscope and multi-meters showing the voltage rise and current draw.

DC Boost Circuit Article

Transistor Latch Circuit

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Multiplexer

Demonstrating a Multiplexer

Taking a look at the SN74LS151N Multiplexer for Hobbyist Electronics

In this video we will take a look at using a Multiplexer (SN74LS181N) to switch between inputs. This demonstration will consist of a breadboard circuit setup to show how multiple inputs can be switched to a single output.

Multiplexer Circuit

Multiplexer Circuit

Using the DIP switches to control the Multiplexer, we can set the ‘Select’ pins A,B,C based on the function/truth table in order to control the device.

DIP Switches

DIP Switches

The use of pull-down resistors for the select pins and the input pins are needed to ensure the pins are not ‘floating’ and instead are pulled to ground (logic low)

Multiplexer Connections

Multiplexer Connections

A Multiplexer can easily be connected via the 3 select pins and a single input to a Micro-controller to provide fast switching capabilities when using multiple external sensors or other input device.

SN74LS151N Datasheet

8-Bit Shift Register

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Demonstrating the LM2907 Frequency to Voltage Converter for Hobbyist Electronics

LM2907 Frequency to Voltage Converter

Demonstrating the LM2907 Frequency to Voltage Converter for Hobbyist Electronics

In this video we will take a look the LM2907 Frequency to Voltage Converter integrated circuit. This will be an on the bench demonstration using the datasheet test circuit with minimal components. Using a Function Generator to provide the source frequency we will monitor using an Oscilloscope the voltage versus frequency and examine the response to a Sweep signal at various rates.

Minimal Component Diagram

Minimal Component Diagram

The following resistor and capacitor values can be changed to affect voltage and frequency range (extract from LM2907 datasheet)

C1: This capacitor is charged and discharged every cycle by a 180-µA typical current source. Smaller
capacitors can be charged quicker therefore increasing the maximum readable frequency. However, lower
capacitors values reduce the output voltage produced for a given frequency. C1 must not be sized lower than
500-pF die to its role in internal compensation.

R1: This resistor produces the output voltage from current pulses source by the internal charge pump. Higher
values increase the output voltage for a given frequency, but too large will degrade the output’s linearity.
Because the current pulses are a fixed magnitude of 180 µA typical, R1 must be big enough to produce the
maximum desired output voltage at maximum input frequency. At maximum input frequency the pulse train
duty cycle is 100%, therefore the average current is 180 µA and R1 = Vo(max) / 180 µA.

C2: This capacitor filters the ripple produced by the current pulses sourced by the charge pump. Large values
reduce the output voltage ripple but increase the output’s response time to changes in input frequency.

Test Circuit

Test Circuit

LM2907 Datasheet

LM567 Tone Decoder

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Digital Potentiometer

Transistor Relaxation Oscillator Circuit for Hobbyist Electronics

Transistor Relaxation Oscillator

Transistor Relaxation Oscillator Circuit for Hobbyist Electronics

In this video we will take a look at a Transistor Relaxation Oscillator circuit. Using a NPN transistor reverse biased in conjunction with a resistor and capacitor, we can create an a simple relaxation oscillator. This demo will show the output waveform and discuss how the circuit works.

Relaxation Oscillator Circuit

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