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The PortaPAL Public Address System-Part 1 - It's packed with features, is easy to build and rivals commercial systems costing much more __ SiliconChip
Thermofan to Keep Your Amp Cool - Use a 12V computer fan to cool your amp. Uses diode temperature sensor f __ Designed by Rod Elliott ESP
Thermostat for 1KW Space Heater SCR controlled - Below is a thermostat circuit I recently built to control a 1300 watt space heater. The heater element (not shown) is connected in series with two back to back 16 amp SCRs (not shown) which are controlled with a small pulse transformer. The pulse transformer has 3 identical windings, two of which are used to supply trigger pulses to the SCRs, and the third winding is connected to a PNP transistor pair that alternately supply pulses to the transformer at the beginning of each AC half cycle. The trigger pulses are applied to both SCRs near the beginning of each AC half cycle but only one conducts depending on the AC polarity. __ Designed by Bill Bowden
Three Transistor Audio Amp 50 Milliwatt - Here is a little audio Amplifier similar to what you might find in a small transistor radio __ Designed by Bill Bowden
Touch Switch using 4011 CMOS
NAND Gate IC - A touch switch is a switch that is turned on and off by touching a wire contact, instead of flicking a lever like a regular switch. Touch switches have no mechanical parts to wear out, so they last a lot longer than regular switches. Touch switches can be used in places where regular switches would not last, such as wet or very dusty areas __ Designed by Aaron Cake
Tube Amplifier Kit - The amplifier kit uses two 11MS8 tubes per channel. The two DC blocking capacitors and the four coupling capacitors are metallized polyester, while Samsung aluminum electrolytic capacitors are used to filter the solid-state power supply.
Tube Amplifiers - This project is finalized, that means it is no longer experimental. This amplifier, altough limited in output power (20W) , has been designed to give the best listening pleasure. No compromise has been made during components choice: the 845 output triode is one of the best tube available today in that range of power for single-ended applications, the driver stage uses a 300B, a long revered audio tube (note that you must use a WE 300B or a Sovtek 300B). This technical choice has been made in some commercial (like Marantz T1) or amateur __ Designed by puechmor @ mygale.org
Tube Car Stereo Amp - YES, a tube amp in a CAR!!! __ Designed by Bob Danielak
Two 9v battery-powered Amps based on the LM386. Schematic & PCB/perfboard layouts. - For better compatibility with effects driving the Little Gem, a FET buffer can be added. Both the Little Gem Mk II (seen below) and Ruby schematics include a simple buffer design. No further circuit modifications are necessary, however the input capacitor value of the amp may need to be adjusted to taste. __ Contact: holler @ runoffgroove.Com
Two Transistor Amplifier - A 2 Watt audio amplifier made from discrete components. This was one of the earliest circuits that I ever designed and built, in Spring 1982. At that time I had only an analogue meter and a calculator to work with. Although not perfect, this amplifier does have a wide frequency response, low harmonic distortion about 3%, __ Designed by Andy Collinson
Two Watt Amplifier - An audio amplifier made from discrete components with 2 Watts audio power into an 8 ohm load. Carlos has used this amplifier on his AM radio for many years. __ Designed by Carlos Feldman
Ultra-Low Distortion Audio Power Amplifier - This is an unusual circuit for an ultra-low distortion power amp. According to my original notes the circuit is dated January 1977 so the circuit is not exactly modern but it is still sufficiently different to be interesting. The circuit was designed and sold as a card by a purveyor of surplus components but, even using mostly manufacturer's rejected transistors, we managed to get about 0.02% total harmonic distortion at 30 watts with a ±25v power supply into 8 ohms. : no bad figure even in these days of MOSFET and ICs. In 1977 anything below 0.1% was considered excellent. And this figure was pretty repeatable without doing much selection. __ Designed by Richard Torrens
Ultra-Low-Noise S-Band Amplifier - 06/04/12 EDN-Design Ideas Use capacitive reactance to save energy while holding a solenoid in the energized position. Solenoid loads generally exhibit large hysteresis. Application of the rated voltage actuates these loads. Once they are in position, however, you can use a significantly lower voltage to thereafter reliably hold them on. A lower sustaining voltage results in less heat production and higher efficiency.__ Circuit Design by Jessica MacNeil
Voice Amplifier - This is a very simple and low cost audio amplifier. Small modification in this circuit can be done to use along with walkman and intercom etc.
Voltage Controlled Amplifier - In truth this, like many (most) VCAs is really a current controlled amplifier but there is really not too much difference since if you want to turn a CCA into a VCA you simply feed the current input from a voltage via a voltage to current converter (a. k. a. 'resistor') __ Designed by Richard Torrens
Weighting Filter for Audio Measurements - For noise measurements. Ideal for use with the AC Millivoltmeter above __ Designed by Rod Elliott ESP
Wireless PA for Classrooms - In large classrooms, many a times the teacher’s voice is not audible to students in the back rows. So the teacher have to literally shout to be heard by every student. __ Electronics Projects for You |
