Android Oscilloscope
OBD2 Engine Rev Counter
OBD2 Diagnostic app
TFT Clock and Thermometer
WiFi, Ethernet
WiFi Thermometer
WiFi ESP8266
Doorbell with SD / EEPROM
SD FAT16/32 for .bmp
PETIT FAT bmp Display
TFT Timer, Thermometer
TFT Oscilloscope
SD Talking Clock
Android Talking Clock
SD Sound Recorder
SD FAT32 wav Player
SD Arduino Recorder
LED Thermometer
LED Timer
LCD Timer
TFT 10MHz Counter
100KHz Counter For PC
1MHz Counter For PC
8 Digits LED Counter
Scope Screen Counter
LCD Module Counter
LCD Arduino Counter
6MHz Android Counter
NIXIE Android Counter
Bluetooth Counters
USB Counter
USB TFT display BMP
USB DS18B20 Sensor
USB Thermometer
USB Meter
USB Oscilloscope
USB Input-Output
USB Input-Output Android
USB 16x2 LCD
Serial TFT Text
Serial Inputs Outputs
Serial Port LCD
MCP3201 on Serial Port
Serial Thermometer
Analogue Signal to Serial
Serial Thermostat
MCP3201 on LPT
Analogue Signal to LPT
LCD Display on LPT
Water Softener
HP Stream 7 docking
3.7V to 5V
Solar Charger
Infrared Decoder
PIC Music
Code Lock
Code Lock with LCD
HOME   Technical Tips


Low power 5V or 9V from 3.7V lithium ion cell. The 5V can power the projects that use LCD, output current up to 10mA. The 9V version can power most digital multimeters that run on PP3, output current up to 5mA. The output voltage is regulated by the zener diode and the output current is limited by the value of L1.

Circuit Description
See also Technical Tips

The hex inverter 4049 CMOS are used as a free running oscillator. BC337 charges the coil when it's on, and when it's off the coil dumps its charge via the diode 1N4148 into the output capacitor.
When output voltage exceeds the zener voltage BC337 is switched on and stops the oscillator until output voltage drops below the zener voltage.
Table for selecting components.

Output R1 R2 R3 Z1 L1
5V 22K 220R 470R 4.7V 220 - 680 uH
9V 10K 2K2 100K 9.1V 1 - 2.2 mH

Cmos 4049UB can also be 4049B.
Equivalent to BC337 can be used.
Coil can be the smallest physical size available.
Resistors are 5% tolerance.



13.02.2015 - 12:48
Name: Zarif
Comment: can I use this with NI-CAD?  2008-2020