Electronic Circuits

The following are links to useful circuits, which can be used to build larger designs.

• 49MHz Toy AM Transmitter - Simple 2 transistor AM transmitter.
• Gyrator - Telephone DC holding circuit.
• DAA - Data access arrangement circuit.
• Energy Harvester Circuit - Harvests energy from a small source such as a piezo buzzer, and boosts the voltage to 3.3V
• Flyback SMPS - Uses an off the shelf flyback transformer to create a 40V boosting power supply, with a non-dissipative snubber.
• High Side Current Monitor - Monitor a load with a high side sensing resistor.
• High Voltage Regulator - Extend the input voltage on any off the shelf voltage regulator.
• HV MOSFET Driver - Drive a complementary pair of MOSFETs with a high voltage supply
• Inverse Voltage Control - Create a voltage inversely proportional to a variable resistor.
• Joule Thief - Drive LEDs with 1.5V using a transformer based oscillator.
• Latching Momentary Switch - Turn any momentary switch into a latching switch with just a few components.
• Latching Relay Driver Circuits - Avoid common pitfalls with relay driver circuits.
• LED Indictor for Relay - Two LEDs show the NO/NC status of a relay.
• Level Translators: 3V and 5V - Interface 3V and 5V logic signals.
• Level-Shifting-Buffer - Unity gain level shifting buffer with PNP bipolar transistor.
• Non-Inverting Op-Amp Level Shifter - Converts a positive and negative signal into a range suitable for a single supply ADC.
• Power On Pulse Circuits - Create a pulse when a circuit turns on.
• Saw Transmitter - Simple 433.92MHz transmitter often used in key fobs.
• SDI-12 Bus Interface - Hardware interface for connecting a microcontroller with a 1200 baud UART to an SDI-12 bus.
• Selectable Voltage Source - Allow a microcontroller to select between two different voltage levels from a standard voltage linear voltage regulator.
• Short-Circuit Protection Circuit - Protect the output of a power amp or power supply from shorts across the output leads.
• Transformerless Power Supplies - Power circuits from wall current, without the use of a transformer.
• Transistor AC OpAmp - A 3 transistor AC OpAmp Circuit.
• Transistor Schmitt Trigger - Schmitt trigger circuit uses two transistors.
• Variable PIN Diode Based RF Attenuator - A great RF Volume Control
• Variable Zener - Voltage programmable zener diode
• Voltage Controlled Current Source - Current Servo - Create a current proportional to a control voltage.
• Voltage Controlled Voltage Source - Create a voltage output proportional to a control voltage.
• Voltage Controlled Voltage Source (Inverse) - Create a voltage output proportional to a negative control voltage.