Skip to main content


Showing posts from July, 2011

1.5V-25V DC Variable Power Supply

This is 1.5V-25V DC Variable Power Supply. The power supply use KR142EN14 or LM317 as regulator component. KR142EN14 or LM317 is capable to handle electric current up to 2A. You may use LT1083/84/85 to handle electric current of 7A/5A/3A. Resistor R9 is used as a current sensor to an ammeter.

Components list:
R1 : 4K3
R2 : 18K
R3 : 100
R4,R8 : 100K
R5 : 1K
R6 : 240
R7 : 4K7 ( Variable resistor )
R9 : 0.33 E
C2 : 0.1uF
C3 : 10000uF/40VC4 : 100uF/25V
D1 : KY202
D2 : KD521
D3 : D311
D4 : KC147
T1 : KT814B
T3 : KT209
T4 : KT3102
IC1 : KR142EN14 (LM317)

Circuit source: 1.5V-25V power supply with preregulator

LT1070 Boost Converter Circuit, 5VDC to 12VDC

This is a converter circuit which will convert 5VDC input to become 12VDC output. The circuit is based LT1070 which also will boost the current output.

About LT1070:
The LT®1070/LT1071 are monolithic high power switching regulators. They can be operated in all standard switching configurations including buck, boost, flyback, forward,inverting and “Cuk”. A high current, high efficiency switch is included on the die along with all oscillator, control and protection circuitry.Boost Converter circuit reference, download: LT1070 datasheet

Cheap Low-Dropout 12V / 3A Linear Regulator

The following diagram is the cheap Low-Dropout linear regulator circuit.

This linear post regulator circuit provides 12 V at 3 A. It applies TL431 reference U1 which, without additional amplification, drives TMOS MTP3055A gate Q1 series pass regulator. Bias voltage is applied through R1 to Q1's gate, which is protected against overvoltage by diode CR1. Frequency compensation for closed-loop stability is provided by C1.

Circuit Characteristics:
Dropout voltage: 0.6 V
Line regulation: ±5 mV
Load regulation: 10 mV
Output ripple: 10 mV pk-pk

NiCd NiMH Battery Charger using PIC16C711

This is the battery chargercircuit for NiCd and NiMH battery tipe. The circuit is using microcontroller PIC16C711 for constant current supply. A constant current supply is switched on and off as required by a micro-controller. The microcontroller senses the battery voltage and internally uses an analog to digital converter to read the battery voltage. The microcontroller, requires its own 5V regulated supply and displays the current charging status on two LEDs. The smallest and cheapest micro-controller that could be used to perform the Analog to Digital function and still have the necessary functions and control lines to do this is the PIC16C711.

Visit this page for full explanation about this NiCd NiMH Battery Charger circuit

Tracking Preregulator circuit

The following diagram is the schematic diagram of tracking preregulator circuit uses LM308, LM360, 2N2905.

15A DC Voltage Regulator

The following circuit diagram is a 15A DC voltage regulator based LM338