transformerless joule thief circuits

This a circuit very similar to a Joule Thief, except that it is using 2 transistors, no transformer core, and only one inductor. Joule Thief based on transformer page is here: I have built these two circuits today and have combined them into one- first stage is the LED torch

Joule Thief and LED torch project instructions

You can find component kits here: This page soon will contain information how to build a classic Joule Thief (Detailed instructions). Here you can see a brand new joule thief (transformer based) I have built. It can produce upto 50 volts from a fresh battery! How it looks in

Digital::CH3::CMOS gate circuitry

CMOS gate circuitry Up until this point, our analysis of transistor logic circuits has been limited to the TTL design paradigm, whereby bipolar transistors are used, and the general strategy of floating inputs being equivalent to “high” (connected to Vcc) inputs — and correspondingly, the allowance of “open-collector” output stages

Digital::CH3::TTL NOR and OR gates

TTL NOR and OR gates   Let’s examine the following TTL circuit and analyze its operation:   Transistors Q1 and Q2 are both arranged in the same manner that we’ve seen for transistor Q1 in all the other TTL circuits. Rather than functioning as amplifiers, Q1 and Q2 are both

Digital::CH3::Multiple-input gates

Multiple-input gates Inverters and buffers exhaust the possibilities for single-input gate circuits. What more can be done with a single logic signal but to buffer it or invert it? To explore more logic gate possibilities, we must add more input terminals to the circuit(s). Adding more input terminals to a

DIGITAL::CH3::The buffer gate

The “buffer” gate If we were to connect two inverter gates together so that the output of one fed into the input of another, the two inversion functions would “cancel” each other out so that there would be no inversion from input to final output: While this may seem like

DIGITAL::CH3::The NOT gate

The NOT gate The single-transistor inverter circuit illustrated earlier is actually too crude to be of practical use as a gate. Real inverter circuits contain more than one transistor to maximize voltage gain (so as to ensure that the final output transistor is either in full cutoff or full saturation),

DIGITAL::CH3::Digital signals and gates

Digital signals and gates While the binary numeration system is an interesting mathematical abstraction, we haven’t yet seen its practical application to electronics. This chapter is devoted to just that: practically applying the concept of binary bits to circuits. What makes binary numeration so important to the application of digital

single cell dc/dc converter PCB BC327 PNP

this is a dc/dc converter PCB I designed a few years ago. One transistor, two coils, and some passive components. It is adjustable. prototype photo actual PCBs are infrared soldered. New revision of the dc/dc converter PCB! It has been tested from 1.2 volts to 5 volts input range. Small PIC circuits can be powered directly from 1.2 volts battery with … Continue reading

FM transmitters

Two FM transmitters were built recently. The first transmitter is based on 7 2n3904 transistors: The second transmitter is based on 3 2sc1740 transistors: Some resistors were made adjustable especially the emitter resistor and the bias resistors. Using other transistors than the originally suggested 2n3904, this is absolutely neccessary. The schematic for the second transmitter: