Ham Radio – How to Read, Draw and Understand Circuit Diagrams

Many new comers to Ham Radio find trying to read and understand a circuit diagram a very daunting task, I have heard some people say that they will never understand how circuits work and how they interact with other circuitry. I was once like that too; none of us was born with knowledge of radio we all need to learn it. The key to understanding is to build simple circuits and understand the laws that tie them all together.

How do you start to learn what component do and how do they achieve it. First of all you must understand that Ham radio is a technical hobby that brings people together from all over the World it’s like a giant social network, every one of those people started somewhere, and here is what I did to help my understanding.

The first law we need to learn is ohms law and how voltage current and resistance is calculated in a simple circuit. You need to buy some resistors, bread board, which is an experimental piece of board where you connect component together by essentially pressing their leads down through the board, small compression clips hold the wires in place. You will also need a meter to measure the various electronic quantities.

You can also us tag board, but you will need a soldering iron, not a bad thing really because if your interest like mine develops into more construction and modifying than actually communicating soldering components on to circuit board is a skill that you will need to practice.

Once you obtain your resistors and the best place to buy them is from the auction websites that you find on the internet. Many sellers provide bags of standard or preferred value resistors very cheaply. Learn ohms law, it not too difficult, Volts is equal to Current multiplied by resistance.

Resistors in series, you simply add them together, 4 ohms plus 4 ohms is equal to 8 ohms, and resistors in parallel with each other effectively half the total resistance, 4×4 = 16, 4+4 = 8, 16 divided by 8 is equal to 2. Solder your components onto your tag board or use your bread board which ever you choose the outcome will be the same. I use bread board for experimental circuits and then usually transfer them on to tag board when making a permanent circuit.

Connect your battery is series and parallel with a battery of about 9 volts and measure the current flowing around the circuit, you need to connect the meter in series with your circuit to measure current, placing the meter probes across a component gives you the voltage across it. There are numerous websites showing you how to do this and some offer an animated description of what is actually happening.

Move onto capacitors and learn the laws surround capacitors in series and parallel, read how the distance of the plates in a variable capacitor change the component; doing so will help you understand how tuning a capacitor alters the frequency in a receiver or transceiver.

Wind inductors or coils with enamelled copper wire onto Dowling which is used as a former, and measure them after you have learnt the core principles of how they work. Understand how the number of coils or turns and diameter of the inductor alters as you change them.

Play around with the coil formula of Diameter of coil squared times, the Number of coils Squared. Divide this by 18 times the diameter of the coil plus 40 times the length of the coil. Keep doing these calculations they seem impossible to you at this stage, but practice makes perfect and before long you will start to understand electronics.

I moved onto building simple crystal sets after learning how individual components work, crystal sets are great fun. If you have developed an understanding of inductors or coils and capacitors you can modify your crystal set to cover other bands once you have learned how coils and capacitors work together as tuned circuits.

Source by John Allsopp