Wide bandwidth RF amplifier Simple wideband RF LNA with bandwidth from under 100 kHz to 2.5 GHz, 10 dBm (10 mW) output power, 50 ohm inputs/outputs, based on the BGA2869 chip, with added power filtering and protection circuits. Modifiable for other BGA28xx series ICs, e.g. BGA2817. Created: 2025/10/26 Last modified: 2025/10/28
DC to 3+ GHz, 50 ohm, 50-100 watt RF load RF load usable at several GHz (at least 3-4 GHz) with good VSWR (about 1.1 at 3 GHz) based on the Florida RF 32-1055 terminator. Capable of handling at least 50 watts continuously. Created: 2025/10/26 Last modified: 2025/10/26
HUSB238 development/testing board (PD trigger) A simple test/dev board for the Hynetek HUSB238 USB-C Power Delivery trigger chip. It is one of the chips commonly found on so-called PD decoy/PD trigger boards. Created: 2025/02/21 Last modified: 2025/02/21
Low power LED flasher 3 Miniature low power LED flasher with current consumption of a few microamperes (µA) and expected battery lifespan of >5 years with a single CR2032 cell, usable for example as a fake alarm. Using only discrete parts. Created: 2025/02/21 Last modified: 2025/02/21
Addressable LED strip/chain controller Controller for addressable LED strips (WS2812/WS2812B) or chains for 5-60 LEDs. Based on the ATtiny85 microcontroller. With music controlled effects. Created: 2023/12/20 Last modified: 2024/01/01
Ultrasonic source Ultrasonic source usable as an educational tool or as a powerful ultrasonic animal repeller. Created: 2023/08/15 Last modified: 2023/08/15
Live wire/cable detector Two versions of a simple circuit usable for detecting live wires - using capacitive coupling. Created: 2021/09/30 Last modified: 2021/09/30
Hot air station Analog hot air station using an 858D handle. Temperature and air flow control. Simple circuit with LM358 - schematic diagram and description. Created: 2020/12/11 Last modified: 2020/12/11
Very low voltage Joule thief - voltage booster for LED Germanium transistor based Joule thief variation able to run on 55 mV. Capable of running an LED using a Peltier module + body heat. Created: 2020/12/11 Last modified: 2020/12/11
Lithium cell charge level indicator Simple charge level indicator for rechargeable cells based on the LM3914 IC. Can be easily modified for other voltages/battery types (Pb...) Created: 2020/12/07 Last modified: 2020/12/07
Nixie clock Small nixie clock based on ATtiny88, DS3231M, MMBTA92, MMBTA42, MC34063 Created: 2020/10/18 Last modified: 2020/10/18
Boost converter for 3 watt UV-C lamp DC-DC converter designed for powering 3 watt UV-C lamps from 3 to 5 volts, including Li-ion batteries Created: 2020/07/24 Last modified: 2020/07/24
Low power LED flasher 2 Low power LED flasher with up to 10 years runtime on a single AA battery Created: 2020/05/04 Last modified: 2020/05/04
9 V Ni-MH charger, LED tester Simple 5 V (USB...) powered 9 V NiMH charger (7.2/8.4 V) also usable as a LED tester Created: 2020/02/25 Last modified: 2020/02/27
Decorative neon lamp supply Simple voltage converter for decorative neon lamps (flicker flame type) operating from a 5 V power supply (for example USB). Created: 2019/12/20 Last modified: 2019/12/20
Inductor saturation current tester Device for testing saturation current of various inductor and measurement of parameters of inductor cores using current up to 50 A. Created: 2019/12/08 Last modified: 2021/03/20
I-V curve tracer Tool for measurement of I-V curves (ampere-volt curve, current-voltage characteristic) using an oscilloscope. Created: 2019/12/07 Last modified: 2019/12/07
Automatic fan control Temperature based automatic fan controller using LM358. Created: 2019/12/07 Last modified: 2019/12/07
Self-oscillating step-down LED driver Two transistor self-oscillating buck (step-down) converter for LEDs (300 mA). Created: 2019/11/29 Last modified: 2019/11/29
Constant current 1W LED driver (II.) A small MC34063 based constant current supply. Used for soldering gun modification (incandescent to LED). Created: 2017/12/09 Last modified: 2017/12/09
Electronic dice ATtiny13 based electronic dice powered by a CR2032 battery. Created: 2017/06/03 Last modified: 2017/06/03
Rechargeable battery analyzer ATmega328P based capacity & internal resistance meter + dummy load Created: 2017/05/28 Last modified: 2017/12/23
Super simple LED flasher An extremely simple circuit. 4 parts total. Created: 2016/09/28 Last modified: 2021/02/22
Low power LED flasher A microcontroller-based flasher with 15uA power consumption Created: 2016/08/24 Last modified: 2016/08/24
Wireless energy transfer Resonant Royer-based wireless energy transfer circuit Created: 2016/06/20 Last modified: 2016/06/20
TDA2003 based amplifier A small 5W/channel amplifier Created: 2016/06/06 Last modified: 2016/06/06
Constant current LED supply MC34063 based switch mode LED current regulator Created: 2016/05/18 Last modified: 2016/05/18