Circuits & Schematics

This circuit is a simple sweep generator. The sawtooth is generated by the PNP transistor and the 555 . The transistor together with the 2 diodes at the base form a constant current source which charges the 330 nF capacitor. If 2/3V CC (=6 V) is ...

Figure 1 shows a variation on a sine wave oscillator, it uses just two transistors and a single variable resistor to set the frequency. Figure 1. Just a couple of components are needed for a simple tunable sine wave oscillator. The section around ...

Driving LEDs at a regulated current from low supply voltages can be difficult because minimal overhead voltage is available for control circuits. A current-mirror architecture is suitable but usually works only with ICs with well-matched ...

This dummy-load circuit has been in use at Maxim for more than 10 years (see the Figure 1). It's useful for testing power supplies and power amplifiers as well as drivers for LEDs, relays, and solenoids. Plus, it overcomes the limitations of ...

Variable regulated power supplies are handy tools found on well-equipped electronics lab benches. The symmetrical varieties that produce equal voltage outputs of opposite polarity, are even more so. Figure 1’s version of a symmetrical 0 V to ...

I needed a simple mist maker/humidifier for a project that I was working on. I found lots of ideas on the internet, but they all lacked in one area or another, so I decided to design one. The following lays out my easy-to-build ultrasonic mist ...

The ubiquitous variable resistance circuit network shown in Figure 1 Figure 1. Classic adjustable resistance; R MAX = R S + R R ; R MIN = R S . But a sticky question remains: What if the polarity of the V A V B differential is subject to reversal? ...

This is one real-life quest: How do we increase the output voltage of a step-up converter? If you have unlimited access to the right ICs, you are one lucky dog, but what if you don’t? Or maybe you are limited to a specific chip due to ...

It’s easy to mute a balanced signal line. Simply short the terminals or break the signal path. But when the line is unbalanced (single ended) and the output has strong dc bias, trying to mute the circuit with these methods will affect the ...

Zeroing out temperature variations on a production line is a challenging task when the device to be compensated has a temperature coefficient that varies in both magnitude and sign from unit to unit. This simple circuit can meet the challenge (see ...