Rongge

In building QRP HF radios, having an RF signal level amplifier building block is handy. You want 50 Ohm output impedance, some reasonable gain, supply voltage of the usual 10-14V and ease of building using standard parts from your parts bin. Some searching around the interwebs came up with a good idea for circuit from Aaron Parks, KC8FQD, who did a YouTube video on a WWV receiver. [ ]

Class A headphone amplifier Class A headphone amplifier

I quite like the look of the Noisy Cricket Mk II amp from Beavis Audio (http://www.beavisaudio.com/projects/NoisyCricket/), and I happened to have a wooden box lying around that looked like it would work great as a 6” speaker cabinet, hence today’s project. (EDIT: Actually it turns out the Mk I and the MK II are the same. The only difference is the PCB design, and since I'm using veroboard, that's irrelevant.) The Noisy Cricket is a little 1/2 Watt guitar amplifier that fits into a standard Hammond-like enclosure (such as the one I used here: http://diystrat.blogspot.com/2013/04/building-modified-ea-tremolo-pedal-on.html). It uses a MPF102 or a 2N5951 transistor as a preamp channel and an LM386 as the power amp. It’s also powered from a standard 9v guitar pedal power supply (or even a battery). What’s not to like? As I usually do, I’m going to use Veroboard for this. A few people have already done layouts for it, and I decided to go with this one: Which can be found here: htt...

This is a Simple Power Pulse Using by LM350 and NE555 Circuit Diagram . This circuit can use to drive lamp,power LED,DC motor etc. Adjust R5 for output amplitude.Adjust R1 for output power . Power Pulse Circuit Diagram The LM350 is adjustable 3-terminal positive voltage regulators is capable of supplying in excess of 3A over a 1.2V to 33V output range.This circuit requires 5-15V power supply.

Here is an interesting circuit , it is used to make a kind of lock or locks for bicycles , it allows owners to implement a bicycle lock and electronic alarm with a low cost . The operation of the electronic lock is simple , it has a circuit that uses a tone generator IC UM3561 , this IC generates a sound when your bike has the protection wire that surrounds the wheel broken .   Blocking Circuit with Alarm for Bicycle Circuit Diagram Click here to download complete project

Rechargeable torches don’t come without problems. You need to replace the bulbs and charge the batteries frequently. The average incandescent light-emitting diode (LED) based torch, for instance, consumes around 2 watts. Here’s a rechargeable white LED-based torch that consumes just 300 mW and has 60 per cent longer service life than an average incandescent torch.  Rechargeable Torch Based on White LED Circuit Diagram Fig. 1 shows the circuit of the rechargeable white LED-based torch. The reactive impedance of capacitors C1 through C3 (rated for 250V AC) limits the current to the charger circuit. The resistor across the capacitors provides a discharge path for the capacitors after the battery is charged. The red LED1 indicates that the circuit is active for charging. The torch uses three NiMH rechargeable button cells, each of 1.2V, 225 mAH. A normal recharge will take at least 12 hours. Each full recharge will give a continuous operational time of approximately 2.5 hours. Recharge...

The RF oscillator using the inverter N2 and 10.7Mhz ceramic filter is driving the parallel combination of N4 to N6 through N3. Since these inverters are in parallel the output impedance will be low so that it can directly drive an aerial of 1/4th wavelength. Since the output of N4-N6 is square wave there will be a lot of harmonics in it. The 9th harmonics of 10.7Mhz (96.3Mhz) will hence be at the center of the FM band . N1 is working as an audio amplifier. The audio signals from the microphone are amplified and fed to the varycap diode. The signal varies the capacitance of the varycap and hence varies the oscillator frequency which produce Frequency Modulation. Source:Fm-transmitter

This is a simple LED as a diode Rectifier Circuit Diagram. In certain situations where the current is not high, we can use the famous LED (LED) and diode rectifier voltage power circuits. The LED can be used without problem in a rectification circuit, and also works in the power ratings. Pay attention not to exceed the maximum current of the LED in a wave rectifier.  Using LED as a diode Rectifier Circuit Diagram

This is a 100 Watt Inverter Circuit Diagram with Veroboard Print (LOW COST). This 100 watt Inverter Circuit use Minimum number of Components.I think it is quit difficult to make a decent one like this with further less components.Here we use {CD 4047 IC} for generating the 100 Hz pulses and four {2N3055} Transistor for driving the load.The IC1 {CD 4047} wired as an Astable  multi vibrator produces two 180 degree out of phase 100 Hz pulse train.These pulse train are preamplifier by the two TIP122 100 Watt Inverter Circuit Diagram Transistor.The output of the TIP122 Transistor are amplified by fout 2N3055 Transistor {Two transistor for each of half cycle} to drive the inverter transformer.The 220 AC be available at a secondary of the transformer.Nothing complex just the elementary inverter principle and the circuit great for small load like a few savers or fans.This is LOW COST inverter only 7 $. Info     12v Car Battery can be use for this Inverter Circuit.  ...