SG3525 PWM Inverter Module Circuit Working Explanation

SG3525 PWM inverter circuit board is a square wave inverter that oscillates the 12V DC input voltage at a high frequency of 18–24 kHz, using an onboard ATX transformer to generate a 220V AC output. This compact inverter is suitable for use as an emergency power supply for AC LED bulbs and adapters.

Specification

The quick technical specification of the circuit board is given below.

Module Type	PWM Inverter
Chip Used	SG3525
Input Type	DC
Input Voltage	12V
Input Current	≤ 2 Ampere
Input Terminal	H1
Operating Frequency	18kHz to 24kHz
Output Type	AC
Output Voltage	220V
Output Terminal	H2
Max Load	5W to 100W
PCB Colour	Purple

Circuit Diagram

Schematic of sg3525 pwm inverter module circuit as shown below.

The components are used in the circuit boards are - U1: SG3525 IC, Q1 Q2: IRF3205 N-Channel MOSFET, TRF1: EE16 High Frequency Transformer, R1: 1K 1/4W Resistor, D1: 3MM Red LED, R2 R3 R6 R7: 2K 1/4W Resistor, R4: 4K7 1/4W Resistor, R5: 200R 1/4W Resistor, R8 R10: 10R 1/4W Resistor, R9 R11: 8K2 1/4W Resistor, C1: 1000uF 16V Electrolytic Capacitor, C2: 1uF Ceramic Capacitor, C3: 1uF 25V Electrolytic Capacitor, and C4: 5nF Ceramic Capacitor.

Circuit Working Explanation

The working principle of the SG3525 inverter circuit is simple. It converts a 12V DC input into a 220V square wave output at a high frequency.

The input DC supply is smoothed and filtered by the parallel-connected capacitors (C1 & C2) and powers the SG3525 IC (U1) through its VC pin (13). A series circuit consisting of a current-limiting resistor (R1) and an LED (D1) emits light to indicate the device is turned on.

The IC is typically a multifunction PWM generator, it is set up in an inverting/non-inverting or push-pull configuration in this module.

Therefore, the inverting input pin (1) receives a low logic signal from the ground through resistor (R1). An internal 5.1V reference is provided through the V_REF pin (16), which supplies a high logic signal from the voltage divider formed by resistors (R3 & R6) to the non-inverting input pin (2).

External resistors (R4 & R5) and a capacitor (C4) are used to set the frequency of the IC's internal oscillator circuit. The CT pin (5) is connected to the capacitor (C4), while the RT pin (6) is connected to resistor (R4) to optimize the frequency. The Discharge pin (7) is connected to resistor (R5) to determine the IC's dead time.

The electrolytic capacitor (C5) is connected to the Soft-start pin (9) to initiate the operation of the IC gradually, preventing a sudden or abrupt start.

The two outputs of the IC (pin-11 & in-14) are switched by the supply connected to the VC pin (13). These push-pull switching outputs efficiently control the n-channel MOSFETs (Q1 & Q2) at high frequencies, typically around 18kHz to 24kHz.

Case 1: When pin (11) is high and pin (14) is low, the gate of MOSFET (Q1) is triggered through resistor (R8). The 12V input supply flows through the primary winding (L1) and completes the circuit via the Drain-Source path of MOSFET (Q1) to ground. This induces mutual induction, stepping up the voltage to 220VAC in the secondary winding (L3). Resistor (R9) acts as a pull-down resistor to keep the gate of (Q1) low during the off condition.

Case 2: When pin (11) is low and pin (14) is high, the gate of MOSFET (Q2) is triggered through resistor (R10). The 12V input supply flows through the primary winding (L2) and completes the circuit via the Drain-Source path of MOSFET (Q2) to ground. This induces mutual induction, stepping up the voltage to 220VAC in the secondary winding (L3). Resistor (R12) acts as a pull-down resistor to keep the gate of (Q2) low during the off condition.

Hence, this oscillation creates an square wave 220V AC voltage in the secondary winding of the transformer (TRF1). The transformer winding turns are: L1 and L2 = 7 turns each, L3 = 150 turns. The switching pulse of IC (U1) is continuously monitored at the Drain of the MOSFETs through resistor (R7).

NE555 Adjustable Delay Timer Relay Module Circuit Working Explanation

NE555 adjustable delay timer relay module is a time-delay switch based on the NE555 timer IC, allowing control of the relay's ON delay from 0 to 10 seconds. The delay can be set via an onboard multi-turn potentiometer. This module helps protect sensitive electronic components and devices from high inrush currents caused by inductive loads during power restoration.

Specification

The quick technical specification of the circuit board is given below.

Module Type	Adjustable Delay Timer Switch
Chip Used	NE555
Input Type	DC
Input Voltage	5V
Input Terminal	+VCC, GND
Power ON Indicator	Red Light
Delay Time Range	Adjustable (0 to 10 Sec.)
Load Terminal	COM, NC, NO
Load Rating	10A at 250V AC /10A at 28V DC Max.
Relay ON Indicator	Red Light
PCB Colour	Red

Circuit Diagram

Schematic of ne555 adjustable delay timer relay module circuit as shown below.

The components are used in the circuit boards are - U1: NE555 Timer IC, C1: 100UF 50V Electrolytic Capacitor, C2: 100nF 0608 SMD Ceramic Capacitor, PR1: 100K Multi-Turn Potentiometer, RLY1: 5V Relay, Q1: S9013 SMD NPN Transistor, LED1 LED2: 0608 SMD Red LED, R1 R2: 1K 0608 SMD Resistor, D1 D2: 1N4148 SMD Fast Switching Diode, H1: 2-Pin Screw Terminal, and H2: 3-Pin Screw Terminal.

Circuit Working Explanation

The working principle of this adjustable delay timer module is simple and involves a combination of two circuits - A monostable timer circuit based on the 555 timer IC, and a relay driver circuit using a transistor.

When the circuit receives a 5V DC input at Vcc terminal (H1), diode (D1) protects against reverse polarity, and power-ON is indicated by LED (LED1). The 555 timer IC (U1) is configured as a monostable pulse generator. In this configuration, capacitor (C1) charges through potentiometer (PR1) from the 5V supply. When the voltage at the trigger/threshold pins rises from below 1/3 Vcc to above 2/3 V_CC, the timer output remains high for a duration (0 to 10 Seconds) determined by the adjustable potentiometer. Capacitor (C2) stabilizes the control voltage.

The timer output is then used as an input signal to the base of the N-channel transistor (Q1) via a turn-ON indicator LED (LED2) and a current-limiting resistor (R2). When the input signal is high (≤ 4V), the transistor becomes forward biased and lets current flow from collector to emitter.

The relay (RLY1) coil is connected between +V_CC and the collector of transistor (Q1). When the transistor is ON, current flows through the relay coil, energizing it and changing the state of the relay contacts — NO and COM contacts close, and NC and COM contacts open. These contacts are used to turn ON or OFF the load connected at terminal (H2).

A flyback diode (D2) is connected in parallel with the relay coil to protect the transistor from high-voltage spikes generated when the relay coil is turned off.

ME2108A50PG Boost Converter Module Circuit Working Explanation

ME2108A50PG module is a power boost converter that provides a stable 5V DC output voltage with a maximum current of 600mA across various input voltages (0.9V, 1.5V, 1.8V, 2.5V, 3V, 3.3V, 3.7V, and 4.2V). It operates at a frequency of 180 kHz, with a typical conversion efficiency of 85%. It can be used to make power banks, drivers for LED flashlights, etc.

Specification

The quick technical specification of the circuit board is given below.

Module Type	Boost Converter
Chip Used	ME2108A50PG
Input Type	DC
Input Voltage Range	0.9V to 6.5V
Input Terminal	Vi, GND (Common)
Operating frequency	180kHz
Output Type	Stable DC
Output Voltage	5V
Output Terminal	Vo, GND (Common)
Output Current	600mA Max.
Efficiency	85%
PCB Colour	Green

Circuit Diagram

Schematic of me2108a50pg boost converter module circuit as shown below.

The components are used in the circuit boards are - U1: ME2108A50PG IC, L1: 22uH 1A SMD Inductor, C1 C2: 10uF 0806 Ceramic Capacitor, and D1: SS14 Schottky Diode.

Circuit Working Explanation

The working of this boost converter is simple and uses few components. The main component of the module is the 3-pin ME2108A50PG integrated circuit. Initially, the IC (U1) operates by rapidly switching its internal transistor on and off, allowing current to flow through the inductor (L1), from the Lx pin to ground, and storing energy in its magnetic field during the "on" phase.

When the transistor turns off, the stored energy in the inductor is released, boosting the voltage and pushing current through the output diode (D1) toward the noise-filtering capacitors (C1, C2).

The Vout pin of the ME2108 IC provides the output voltage feedback, which is compared with a stable internal reference voltage (Vref) to generate an error signal. This signal adjusts the duty cycle at a frequency of up to 180 kHz to maintain a stable 5V output voltage with a maximum current of 600mA.

MT3608 Boost Converter Module Circuit Working Explanation

The MT3608 module is a DC-DC boost converter circuit board that can step up an input voltage from 2V to 24V to an output voltage ranging from 3V to 28V with 93% efficiency. It operates at a switching frequency of 1.2MHz and can provide a maximum output current of up to 2A. The output voltage can be adjusted using a multi-turn potentiometer. This module is suitable for use as an LED driver or to power battery-operated devices.

Specification

The quick technical specification of the circuit board is given below.

Module Type	Boost Converter
Chip Used	MT3608
Input Type	DC
Input Voltage Range	2V to 24V
Input Terminal	+VIN, -VIN
Operating frequency	1.2MHz
Output Type	Adjustable DC
Output Voltage	3V to 28V
Output Terminal	+VOUT, -VOUT
Output Current	1.2 Ampere Max.
Efficiency	93%
PCB Colour	Blue

Circuit Diagram

Schematic of mt3608 boost converter module circuit as shown below.

The components are used in the circuit boards are - U1: MT3608 IC, C1 C2: 22uF Ceramic Capacitor, L1: SMD 22uF 2A Inductor, D1: SMD SS34 Schottky Diode, PR1: 100K Multi-Turn Potentiometer, and R1: 2.2K 0608 SMD Resistor.

Circuit Working Explanation

The working principle of this boost converter module circuit is simple, where the main component is the 6-pin SOT23 package MT3608 integrated circuit.

When the circuit receives a DC input voltage ranging from 2V to 24V, capacitor (C1) filters out input voltage noise. Initially, the IC (U1) operates by rapidly switching its internal transistor on and off, allowing current to flow through the inductor (L1), from the SW pin to ground, and store energy in its magnetic field during the "on" phase. The MT3608 integrates a fixed 1.2 MHz frequency peak current mode boost architecture to regulate the voltage at the feedback pin and adjust the current (up to 2A) flowing through L1.

When the transistor turns off, the stored energy in the inductor is released, boosting the voltage and pushing current through the output diode (D1) toward the noise-filtering capacitor (C2) and the load. The potentiometer (PR1) and resistor (R1) form a voltage divider that sets the IC's feedback reference and adjusts the output voltage from 3V to 28V.

3.3V/5V MB102 Breadboard Power Supply Module Circuit Working Explanation

3.3V/5V power supply circuit board is compact and designed to provide stable and regulated DC power for MB102 breadboard-based electronics projects. The input voltage range of +6.5V to +15V DC is supplied through a barrel jack or USB connector. The module features dual selectable voltage rails (3.3V or 5V) on both the left and right outputs via jumper settings, allowing flexible powering options for different components with up to 800mA of continuous current. It includes onboard AMS1117-3.3 and AMS1117-5.0 voltage regulator chips for stable voltage conversion, an ON/OFF switch, and a power-on indicator LED. The USB 2.0 output port supplies a convenient +5V source for USB-powered devices.

Specification

The quick technical specification of the circuit board is given below.

Module Type	Power Supply
Chip Used	AMS1117-3.3, AMS1117-5.0
Input Type	DC
Input Voltage Range	6.5V to 15V
Power Button	DPDT Push Switch
Power-ON Indicator	Green Light
Input Terminal	2
Output Type	Fixed DC
Output Voltage	3.3V /5V
Output Terminal	6
Output Current	800mA Max.
PCB Colour	Black

Circuit Diagram

Schematic of 3.3V/5V mb102 breadboard power supply module circuit as shown below.

The components are used in the circuit boards are - U1: AMS1117-3.3 IC, U2: AMS1117-5.0 IC, J1: Female Barrel Jack, SW1: DPDT Push Switch, D1: SMD 1N4007 Diode, C1 C3 C4: 100nF Ceramic Capacitor, C2: 47uF 50V Electrolytic Capacitor, LED1: Green 3mm LED Light, R1: 1K 1/4W Resistor, USB1: USB 2.0 Female Connector, H1 H2: Male Header 4-Pins, H3 H4 H5 H6: Male Header 2-Pins, and H7: Male Header 4X2-Pins.

Circuit Working Explanation

The working principle of the 3.3V/5V power supply module for the MB102 breadboard is simple. The main components are AMS1117-3.3 and AMS1117-5.0 voltage regulator chips. When power is connected to the barrel jack (J1) and the switch (SW1) is turned ON, current flows through the reverse polarity protection diode (D1) to the circuit.

First, the 5V voltage regulator IC regulates the input voltage down to 5V. A green LED (LED1) with a current-limiting resistor (R1) is connected across the 5V output to indicate the power-on status. Then, the second voltage regulator IC (U2) steps down the 5V DC to 3.3V DC. Capacitors C1, C3, and C4 are used to filter out noise from the circuit, while capacitor C2 smooths the input voltage for IC U2.

There is also a USB connector (USB1) connected to the 5V supply, which can be used either as an input to power the module or as a 5V USB output source.

The rail output voltage selector is located on the top of the PCB via male header pins (H1 and H2), while the bottom male header pins (H3, H4, H5, and H6) provide connections for powering external components on the breadboard. Additionally, male header pins (H7) on the PCB provide output pins: two for +3.3V, two for +5V, and four for ground.

LM317 Adjustable Voltage Regulator Power Supply Module Circuit Working Explanation

The LM317 adjustable voltage regulator power supply module converts an input voltage of 4V to 35V DC into a stable, variable output of 1.25V to 27V DC with a maximum current of 1.2A. It has a built-in multi-turn potentiometer for easy voltage adjustment, which makes it ideal for powering electronic modules and testing DIY circuits.

Specification

The quick technical specification of the circuit board is given below.

Module Type	Power Supply
Chip Used	LM317
Input Type	DC
Input Voltage Range	4V to 35V
Input Terminal	1
Output Type	Variable DC Voltage
Output Voltage Range	1.2V to 27V
Output Terminal	1
Output Current	1.2 Ampere Max.
PCB Colour	Blue

Circuit Diagram

Schematic of lm317 adjustable voltage regulator power supply module circuit as shown below.

The components are used in the circuit boards are - U1: LM317 IC, C1: 100nF 0608 SMD Ceramic Capacitor, R1: 220R 1/4W Resistor, PR1: 10K Multi-turn Potentiometer, C2: 47uF 50V Electrolytic Capacitor, and H1 H2: 2-Pin Screw Terminal Connector.

Circuit Working Explanation

The working of the adjustable voltage regulator power supply module based on the 3-pin LM317 integrated circuit is simple.

When an input voltage in the range of 4V to 35V is applied to the input connector (H1) of the circuit board. Capacitor (C1) protects against noise from the input source, especially if the source is more than 6 inches away from the module.

Initially, the LM317 chip develops and maintains a nominal reference voltage of 1.25V (V_REF) between its output and adjustment terminals. This reference voltage is converted into a programming current (I_PROG) by the fixed resistor R1, and this constant current flows through potentiometer (PR1) to ground. By adjusting the potentiometer, a wide range of stable DC output voltages (1.2V to 27V) can be obtained, with a maximum current of 1.2A. Capacitor (C2) smooths the output voltage, which is available at the terminal (H2).