Hobby Circuits designed by Dave Johnson

Last Updated on: Tuesday, June 01, 2021 03:22 PM


Text & Graphics Copyright © David A. Johnson, PE  --  ALL Rights Reserved.
LINKING to Dave's circuits is permitted but COPYING CONTENT to your WEB SITE server IS NOT!

LED Camping Lantern with Dimmer

LED Driver-Wireless

LED Flasher needs only 1.5 VOLTS

LED Flasher that is Battery Free

LED Flasher Universal 3v

LED Flasher-Wig/Wag

LED Flasher-Wireless Circuit

LED Lighthouse Flasher

LED Lighthouse Flasher for HO Model Train

LED Strings powered by AC Line

LED Test Signal Generator-40Khz

Light to Frequency Converter

Line Powered High Intensity LED Flasher

Low Current Flashing LED Power Indicator

Low Power LED Flasher

Low Power Sequential Flasher using 10 LEDs

Mechanical_Underground_Gate_Opener

Model Airplane Wing Tip Flasher

Model Train Lighthouse Flasher Revisited

Modified LED Night Light

Momentary Touch Activated Switch

Monitor ON/OFF status of a Remote Switch

One-Watt White LED Night Light

Optical Filter using Color Film Negative

Over-Temperature Micro-Power Alarm

Protects from Battery Polarity Reversal

PWM Circuit for Motor Speed Control

PWM Motor Controller uses a 555 Timer

Ramping Lamp Driver

Reduced Power Sequential LED Flasher

Remote Range Extender TV/VCR

Remote TV Camera Power

Replace a Pushbutton Switch with this Infrared Safety Switch

Safety Light

Service Request Beeper

Servo Pulse to Voltage Converter

Shop Safety Light

SSR Requires Ultra Low Control Current

Table_Service_Request_Flasher

Target_Shooting_Flasher

Thermostat for 12v Cooling Fan

Three Volt Universal LED Flasher

Three-Volt Low Battery Voltage Flasher

Three-Volt Powered Super Bright LED Flasher

Transistor-Switch Detects Audio Signal

Transmitter for Line Powered Xenon Flash

TV-VCR Light Source 40Khz Repeater

Ultra_Low_Control_Current_Isolated_Relay

Universal Flasher using a Latching Relay

Water Filling Station Controller

Water Pump controlled by Solar Power

White LED Array that is Lined Powered 

12 Volt Lite/Dark Lamp Switch

12v Brush Motor Speed Controller

12v DC Motor with Logic Controlled Automatic Brake

14v LED AuxiliaryLamp with a 60 Watt Lamp

1W White LED Night Light

2 Pushbutton Motor Controller

3 Minute LED Closet Light

3v Powered Super Bright LED Flasher

3v Universal LED Flasher

50ua Current Drives Solid State Relay Requires Only

AC Line Powered LED Flasher

AC Line Under/Over Voltage Alarm

Alarm Sounds At Freezing Temperatures

Automatic DC Motor Brake

Battery-Powered Freezer Alarm

Battery-Powered LED Flashing Advertising #2

Bi-Directional Charge Coupled Powers MOSFET Relay

Boost Infrared TV/VCR Remote Signal

Capacitance Touch Switch

Characteristics of CMOS Logic Inverter Amplifiers

Classic Linear 5v Supply using 6.3VAC Transformer

CMOS IC Flashes LED

Control Variable LED Intensity

Controlled Up/Down Ramping Light

Controller for a 9v Powered Xenon Photoflash

Cooling Fan Thermostat (12v)

CT Hour Meter

CW & CCW Alternating Motor Driver

Dark Activated 12v Power Supply Switch

Detect Short Xenon Lamp Flashes

Detector/Switch for Audio Signal

Detects Low Voltage 120VAC Power Line

Detects Xenon Lamp Flash

Digital noise generator

Drive a LED with an Intensity Ramping Mode

Flashing High-Power LED

Flashing LED Advertising Badge #1

Fluorescent Lamp Intensity Modulator

Fluorescent Lamp Night Light Needs Only 1 Watt

High-Power_Flashing_LED

HO Model Train Lighthouse Flasher

HO Train Lighthouse Flasher Revisited

Increased power for LED Flasher

Infrared Remote Extender Circuit

IR TV/VCR Remote Booster