6-transistor H-bridge

6-transistor H-bridge

6-transistor H-bridge

This is a six-transistor "Tilden-style" H-bridge; although not as old as the original "basic H-bridge," it has a long history and is the basis of many beam driver circuits.

* Maximum capacity of 800 mA (using PN2222 and PN2907 transistors)

Each bridge has 30 connections (therefore, if making a PCB, there are 30 holes).

* Not "smokeproof" (i.e., it cannot handle bidirectional drive voltages simultaneously).

Provided by Bruce Robinson, here are diagrams of inverting and non-inverting types for freely building this circuit (note that these are drawn in "dead bug" style, i.e., pins facing up).

Ian demonstrated a 100k input resistor. I've been successfully using a 47k resistor. Tilden's article suggests no less than 50k (which I think 47k is close enough) and up to around 20 megohms.

I also noticed a slight decrease in speed when using these bridges, but only by about 10%.