Electronics Design

Curve tracers

Curve tracing is a classic way to learn more about many electronic components. Curve tracing is essentially a means of making a graph of current (I) versus voltage (V) called an I-V curve, to display the basic characteristics of an electronic device. I-V curves of the components are helpful in understanding their limitations and nonlinear

Old logic analyzer and probe cables

I got an old HP mixed signal oscilloscope HP54645D. This is over 20 years old test instrument with CRT display. The 54645D is a 100 MHz, 2+16 channel Mixed Signal Oscilloscope from Agilent. Measure voltage or current signals over time in an electronic circuit or component to display amplitude, frequency, rise time, etc. Applications include

Lithium charging security

Don’t do this! (There’s a much safer way) https://www.youtube.com/watch?v=M88e1r8nvYk Big Clive discovered there’s a “thing” going around where people are charging lithium cells by attaching a stripped USB lead directly to them. Normally lithium cells are very safe if undamaged and correct charging procedures are used. But overcharging them like this can result in cell

Speaker to line level attenuator

I saw in Facebook DIY audio group a question about suitable voltage divider resistance values to step down an amplifier’s output (approx 28vrms) to for example around 2.8v. The aim is to use the speaker outputs of an integrated amplifier or AV receiver to run an external power amplifier. Its obvious that a 10:1 ratio

Audio transformer DC

Transformers will only work with a changing current (AC). Transformer only works on AC and can’t be operated on DC i.e. it has been designed to be operated only and only on alternating current and voltage. The transformer works on the principle of mutual induction, for which current in one coil must change uniformly. The

Velleman K7000 signal tracer / injector

This signal tracer/injector has been designed to inject or detect a specific signal into an audio circuit in need of repair (such as amplifiers, radios, tone controls, …) so as to detect the fault. Signal tracer/injector is typically used when testing audio frequency circuits (there are also tracer/injector circuits for other applications as well). With