Rongge

Here is a simple circuit for boosting 12 V DC to 24 V DC .The circuit is designed straight forward and uses few components.With few modifications the circuit can be used to boost any voltages. The transistor Q1 and Q2 (D1616)  essentially drives the primary of the transformer.The diodes rectifies the output of transformer to obtain a 24V DC at the output load(here a fan).The capacitors filter away noise and harmonics away from the output. Simple Voltage Booster Circuit Diagram : Notes. The component values are not very specific here.We can use any NPN power transistors like D1616,2N 3055,C2236,SL 100 etc for Q1 and Q2. The transformer can be any center tapped 5A transformer with a  7:1 winding ratio. The diodes can be 1N 914 ones. In fact you can easily assemble the circuit from the components in your electronics junk box. By experimenting on the tranformer winding you can get different boost ratios. For high current (around 5A)  games use 2N 3055 transistor or more powerf...

This is a simple Audio Booster Circuit Diagram Project . The amplifier's gain is nominally 20 dB. Its frequency response is determined primarily by the value of just a few components-primarily C1 and R1. The values of the schematic diagram provide a response of ±3.0 dB from about 120 Hz to better than 20,000 Hz.Actually, the frequency response is ruler flat from about 170 Hz to well over 20,000 Hz; it's the low end that deviates from a flat frequency response.  The low end's roll-off is primarily a function of capacitor C1(since RI's resistive value is fixed). If C1's value is changed to 0.1 pF, the low end's comer frequency-the frequency at which the low-end roll-off starts-is reduced to about 70 Hz. If you need an even deeper low-end roll-off, change C1 to a 1.0 pF capacitor; if it's an electrolytic type, make certain that it's installed into the circuit with the correct polarity, with the positive terminal connected to Q1's base terminal. Audio B...