Popular Schematics
This section collects classic, time-tested circuits that appear in thousands of real designs: 555 timer blocks, LM317 regulators, 2N3055 power stages and other “workhorse” schematics. Each page focuses on one building block with:
- simple diagrams and block-level explanations,
- typical values and design hints,
- notes on layout, thermal limits and failure modes.
Quick navigation
Timers & Pulse Circuits (NE555 and friends)
- NE555 Astable Oscillator (Square-Wave Generator) – simple clock / PWM source, LED flasher, tone generator.
- NE555 Monostable (One-shot Timer) – delay-on, delay-off, debouncing, pulse stretching.
- NE555 PWM Controller – simple dimmer / motor speed control with duty adjustment.
Linear Regulators (LM317, 78xx, LDO)
- LM317 Adjustable Regulator – Basic Configuration – 1.25–30 V lab-style supply with two resistors.
- LM317 + Pass Transistor for Higher Current – 2–5 A adjustable supply using external power transistor.
- 78xx Fixed Regulators – 7805 / 7812 – “classic” 5 V / 12 V rails with input/output capacitors.
Power Stages with 2N3055 and Similar Transistors
- 2N3055 Linear Power Supply Stage – series-pass regulator with decent heatsinking.
- 2N3055 Class-AB Audio Amplifier – simple “vintage” amplifier topology for experiments.
- 2N3055 as Electronic Load / Power Switch – DC loads, battery testing, power resistive loads.
Other Classic Building Blocks
- Non-Inverting Op-Amp Amplifier – universal gain block with defined bandwidth.
- Op-Amp Comparator with Hysteresis – basic Schmitt trigger for clean switching.
- Mains Bridge Rectifier + Capacitor Filter – the front-end of most linear PSUs.